This work was supported by R01NS075062-01A1. FACS sorting performed at UAB Comprehensive Flow Cytometry Core facility (P30 AR048311, P30 A1027767). Dr. Scott Philips from the UAB Neurobiology Core facility and Dr. Susan Nozell from UAB CDIB assisted with technical aspects of the luciferase assay.

모든 동물은 건강 지침의 국립 연구소에 따라 처리되었다. 버밍엄에서 알라바마 대학의 동물 관리 및 사용위원회는 동물의 사용을 승인했다. 1. 전체 뇌 조직에서 성상 (FACS)을 정렬 형광 활성 셀을 사용하여 풍부한 성상 세포 인구에서 RNA와 DNA를 얻기 <ol><li> 1 분 동안 이산화탄소 후 빠르게 목을 벨과 진정 동물. 앨버 커키 등의 알에 설명 된대로 피질을 해부, 26.; 그것은 수막을 제거 할 필요가 없다. 참고 :. S100β에서 eGFP는 (성상 세포 마커) 프로모터를 발현하는 형질 전환 쥐 이타 쿠라 등 (27)에 의해 생성 및 성상 세포의 FACS 정렬을 위해 사용되었다. </li><li> 제조사의 프로토콜에 따라 비 멸균 조건 하에서 파파인 해리 키트를 사용하여 전체 뇌 균질 물을 준비한다. 10 분 동안 물을 욕조에 37 ℃에서 파파인을 열 활성화합니다. 노트 :파파인 솔루션은 제조업체에서 제공 및 L 시스테인 및 EDTA를 (재료의 표 참조)이 포함된다. <ol><li> 절단 또는 튜브는 95 % O 2 반송하도록 50 ㎖ 원뿔형 튜브의 상단에 구멍을 드레 멜 : 5 % CO 2는 폐쇄 원추형 튜브에 공급되는 (도 1a 참조). 해리 미디어 함유 10mm 배양 접시에 해부 피질 배치 (하여 20 mM 글루코스 및 페니실린 / 스트렙토 마이신 (500 U / ml)로 보충 된 95 %의 O를 평형화 MEM을 2 : 5 % CO 2) (1)에 조직을 말하다 깨끗한 면도날을 사용 X 1mm 2 개. </li></ol></li><li> 파파인 함유 용액 50 ㎖ 원뿔형 튜브에 10 ㎖를 사용하여 수동 pipetman 전사 조직. 조직이 이월 해리 미디어의 양을 최소화하기 위해 배출 전에 전송 피펫의 바닥에 정착하도록 허용합니다. 95 % O 2로 평형화 파파인 용액을 보관 : 5 % CO 2 항온 처리 기간 동안 표면을 통하여 가스 교환. 하지 거품 파파인 soluti를 수행에. 37 ° C의 물을 욕조에 20 분 동안 조직을 품어. </li><li> 파파인 솔루션에 다음과 배양, 씹다 조직 느린 속도로 10 ml의 전송 피펫으로 10 배. 실온에서 5 분 1,000 XG에 원심 분리기 흐린 세포 현탁액. <ol><li> 표면을 통한 가스 교환 (제조사에 의해 제공된)의 DNase / 억제제 알부민 용액과 평형의 DNase / 억제제 알부민 용액 3 ml의 세포 펠렛을 다시 일시. 제조업체의 지침에 따라 상업 불연속 밀도 기울기를 준비합니다. </li></ol></li><li> 6 분 동안 1,000 XG 불연속 밀도 구배 스핀. 피펫을 사용하여 바닥 펠렛을 흡입에 의해 튜브의 바닥에서 해리 세포를 분리. </li><li> 0.02 % 소 혈청 알부민 및 1 ㎎ / ㎖의 DNase 또는 배양 배지 HEPES 완충 바람직 DPBS로 2-3 ml 중에 해리 된 세포를 다시 일시 중지. FACS (그림 2A) 전에 40 μm의 필터를 통해 전달합니다. 정렬 될 때까지 얼음 세포를 유지합니다. <ol><li> 외과 (28)를 수행합니다. &lt;/ 리&gt; <li> 4 ℃에서 5 분 2,000 XG에 1.5 ㎖의 원심 분리기 튜브에서 펠렛 세포. 주 : 펠릿의 성상은 즉시 사용 또는 DNA 추출까지 -80 ° C에 보관 될 수있다. </li></ol></li><li> RNA와 DNA를 선호하는 분리 방법 (29) (30)를 사용하여 압축을 풉니 다. 분광 광도계와 bioanalyzer (31)를 통해 RNA 및 DNA 농도와 품질을 평가합니다. 주의 : 후속 단계에서 단지 고품질 RNA 및 DNA를 활용하여 각각 280분의 260 = 2.0~2.2 및 1.8-1.9를. Bioanalyzer 분석은 RNA 분해 또는 DNA 파편에 대해 평가하는 것이 필수적이다. RNA 또는 DNA는 즉시 사용하거나 또는 -20 ° C, 각각 후속 연구를위한 C °에서 -80 저장할 수 있습니다. </li></ol> 2. 메틸화에 민감한 고해상도 용융 분석 (MS-르마)를 사용하여 유전자의 DNA 메틸화 상태를 평가 <ol><li> 유전자에 어떤의 CpG 섬을 식별하는 것이 바람직 온라인 메틸화 매핑 소프트웨어에 관심의 유전자 서열을 입력관심 (32). <ol><li> 중아 대해 디자인 된 프라이머는 DNA 서열 (33)를 변환하여 제조사의 프로토콜에 따라 바람직한 DNA 중합 효소를 이용하여 증폭한다. 45 분 동안 100 V에서 1 % 아가 로스 DNA 젤을 실행하여 증폭 산물의 크기를 확인합니다. -20 ° C에서 20 μM의 재고 농도 스토어 프라이머. </li></ol></li><li> 중아는 같은 동물 종 (34)로부터 0~100%에 이르기까지 각각의 샘플과 메틸화 된 DNA 표준 DNA의 500 ~ 1,000 NG를 변환합니다. 용출 시료 20 NG / μL의 농도를 제공한다. 분광 광도계 (31)를 통해 중아 변환 된 DNA의 농도를 확인합니다. </li><li> 표 1 및 2에 따른 5 μM 농도에서 바람직한 DNA 폴리머 라제 및 프라이머를 사용하여 MS-HRM 증폭 용 셋업 20 μL 반응. 중으로, FACS의 DNA 메틸화 및 표준을 포함하여 모든 샘플을 실행할. </li><li> 분석 소프트웨어에 따라, 미리 설정하고 시작 매개 변수를 중지 포스트용융 곡선의 천이 주위. 세트 미리 용융 개시 및 둘 사이의 차이가 0.​​2 정도로 미리 용융 정지 파라미터 - 0.5 ° C. 후 용융 시작 및 사후 용융 유사 중지를 설정합니다. 각 샘플에 대한 피크 온도 차이 데이터의 압축을 풉니 다. </li><li> 메틸화 백분율 기준 (Y 값)과 대응하는 평균 피크 온도차 (x 값)을 사용하여 선형 회귀 방정식 (도 3A-B, 표 3-4)을 생성한다. 미지 시료 (35)의 메틸화 상태를 추정하기 위해 선형 회귀 방정식을 사용합니다. </li></ol> 3. 루시퍼 라제 분석의 사용을 통해 하이퍼 메틸화 발기인 활동 평가 <ol><li> 표적 유전자 (2.1 단계)의의 CpG 섬을 식별합니다. 이 PCR의 CpG 섬 luc2-37 플라스미드를 제조 luc2 반딧불 루시퍼 라제 리포터 유전자의 상류에 관심 36 클론의 영역을 증폭. </li><li> 제한을 통해의 CpG 섬 - luc2 플라스미드의 30 μg의 선형화효소 소화 38. 제한 다이제스트에 대한 사이트를 확인하고 원하는 커터 소프트웨어 (38)를 사용하여 두 번 상처를 피할 수 있습니다. 제조 업체의 프로토콜에 따라 소화를 다음과 같은 적절한 온도와 시간에 효소를 열 - 불 활성화. DNA의 최소 손실은 선형화 단계에서 발생합니다. </li><li> 30 ° C에서의 CpG 메틸화 (M.Sssl) O / N을 사용하거나 다음과 같은 조정을 제외하고 처리되지 않은 다음과 같은 제조 업체 프로토콜을 남겨 메틸화 선형화 플라스미드. </li><li> 50 μL 반응을 수행합니다. </li><li> 선형화 플라스미드 700 NG 메틸화에의 CpG 메틸화의 5 단위를 사용합니다. </li><li> 13 ~ 19 시간 동안 반응 O / N을 실행합니다. </li><li> 의 CpG 메틸화 반응에 따라, 시판되는 실리카 - 겔 막의 제조 업체의 프로토콜에 따라 키트를 정리 표준을 사용하여 DNA 정리를 수행합니다. DNA의 상당한 손실은 메틸화 된 CpG 반응 30-60 %의 감소에 따라 발생한다. </li><li> HPA II 제한 다이제스트를 통해 플라스미드의 메틸화를 확인합니다. </lI&gt; <li> 메틸화 또는 비 메틸화 된 DNA 1 μg의를 가지고 제한은 37 ℃에서 1 시간 동안 HPA II 다이제스트. 각 μg의 DNA를 위해 HPA II의 5 ~ 10 단위를 사용합니다. HPA II 소화에 따라, 선호, 시판되는 실리카 - 겔 막 청소 키트를 사용하여 DNA 정리를 수행합니다. 시각화를위한 45 분 (그림 4B) 100 V에서 TAE 나 TBE 버퍼에 1 % 아가 로스 DNA 젤에 모두의 CpG 메틸화 및 비 메틸화 된 플라스미드를 실행합니다. </li><li> 적절한 제한 효소와 더블 소화에 따라 모두 메틸화 및 비 메틸화 플라스미드는 전체 길이 루크 2 (벡터)과의 CpG 섬 (삽입) 38 조각을 분리합니다. 제조 업체의 프로토콜에 따라 소화 다음 적절한 온도와 열을 비활성화 효소에서 더블 소화 O / N을 수행합니다. DNA 농도의 손실을 최소화 이중 제한 다이제스트 동안 발생합니다. </li><li> O를 분리 할 수​​ 있도록 1 시간 동안 100 V에서 1 %의 DNA 아가 로스 젤을 두 번 소화 플라스미드를 실행F 벡터 삽입 (그림 4C). 주의. 보호 자외선 얼굴 가리개를 착용, 밴드를 시각화 탁상 블랙 라이트에 DNA 젤을 배치합니다. 깨끗한 수술 블레이드를 사용하여 크기, 소비세 메틸화 및 비 메틸화 삽입 및 비 메틸화 된 벡터 기준으로합니다. </li><li> 포화 페놀, pH가 6.6을 사용하여 젤 추출 DNA. 간단히, 벡터 또는 삽입을 포함하는 DNA 젤 무게. DNA 젤 0.1 g 당 페놀의 100 μl를 사용합니다. 유리 다운스 균질 기에서 페놀을 사용하여 DNA 겔 균질화. </li><li> 클로로포름 (페놀 량의 1/5 사용)을 추가하고 20 초 동안 샘플을 흔들. 2 ~ 3 분 동안 실온에서 샘플을 품어. 4 ° C에서 최대 속도 (16.1 X 1,000 XG)에서 15 분 동안 원심 분리기. </li><li> 수용액을 제거하고, 3 M 아세트산 나트륨 및 에탄올 2.5 배 부피의 0.1X 볼륨. -80 ° C에서 1 시간 동안 샘플을 품어. 인큐베이션 후, 에탄올을 제거하고 바람직한 완충액 30 μL에 DNA를 다시 일시. DNA의 상당한 손실이 삽입 및 벡터의 다음 분리를 발생, 30 % ~ 50 % 싸다SS. </li><li> 재 결찰을 메틸화 및 비 메틸화 된 인서트 T4 DNA 리가 제 (38)를 이용하여 벡터를 비 메틸화. 결찰 반응에 삽입하는 벡터의 4 비율 : 1을 사용합니다. 제조업체의 지침에 따라 설치 반응. 반응 50 μL의 총 부피를 사용하여 C ° 또는 얼음 양동이 위에 뚜껑 얼음에 -20 O / N을 품어. </li><li> 결찰 후, 선호, 시중에서 판매하는 실리카겔 막 청소 키트를 사용하여 DNA 정리를 수행합니다. DNA의 상당한 손실은 연결 반응, DNA의 대략 30 % ~ 50 %의 손실에 따라 발생한다. 45 분 동안 100 V에서 1 % 아가 로스 DNA 젤에 실행하여 재 결찰을 확인하고 재 결찰 플라스미드 (그림 4D)의 농도를 평가합니다. </li><li> 제조사의 프로토콜에 따라 상업적 형질 전환 시약을 이용하여 세포 내로 D54 메틸화 또는 비 메틸화 된 플라스미드를 형질 감염. 잘 0.14 × 10 6 세포 / 12 웰 판에 씨앗 D54 셀. </li><li> 24 시간 후, 형질 세포 위스콘신(1) 비 methyated의 CpG-luc2 플라스미드 + 레 닐라 또는 다른 제어 루시 페라 벡터 또는 (2) 메틸화 된 CpG-luc2 플라스미드 + 레 닐라 또는 다른 제어 루시 페라 벡터 중 하나의 일 동일 농도. </li><li> 세포가 듀얼 루시 페라 제 분석을 수행하기 전에 24 시간 동안 형질을 허용합니다. 제조업체의 지침에 따라 분석을 수행합니다. 루미를 사용하여 측정을 수행합니다. 세중에서 잘 각을 읽어보십시오. </li><li> 레 닐라하는 반딧불 루시 페라 제 활동의 비율 또는 기타 제어 루시퍼 라제 활성을 계산합니다. 비 메틸화를 제어 반딧불 루시페라아제 활성 : 메틸화 반딧불 정상화 제어 루시퍼 라제 활성을 비 메틸화 된 루시퍼 라제 활성에 의해 메틸화 된 루시퍼 라제 활성을 나누어 </li></ol>

The authors have no disclosures.

This protocol describes the isolation of an enriched population of astrocytes via FACS as well as a variety of techniques that allow for both correlative and causative studies between DNA methylation and gene expression. These techniques, used in isolation or in combination, are particularly useful for laboratories that work with tissue of high cellular heterogeneity or are interested in the DNA methylation status of a particular gene or gene region versus global DNA methylation changes. One relatively unique challenge i...

Epigenetics is the study of chemical modifications that can affect the transcriptional activity of the genome. Essentially, without a change in the DNA sequence, epigenetic modifications such as DNA methylation, histone acetylation, and histone methylation are sufficient to reversibly alter patterns of gene expression 1. DNA methylation, a potent regulator of gene expression, is the most well characterized epigenetic modification. DNA methylation is the covalent attachment of methyl groups on the C5 position of a cytosine, typically the cytosine of a cytosine-guanine dinucleotide, also known as a CpG site. Areas that contain a high density of CpG sites are known as CpG islands (CGIs). CGIs are frequently associated with transcriptional start sites (TSS) and gene promoters 1-3. Thus, while changes in DNA methylation at CGIs are not always concomitant with changes in cellular expression or function, changes in DNA methylation at CGIs can exert powerful regulation on transcriptional activity 2. 
Historically, DNA methylation was observed to be essential in embryogenesis, imprinting, and development, with little changes in the levels of DNA methylation occurring in post-mitotic cells (with the exception of alterations in cancer-related genes) 4,5. However, the field of neuroepigenetics has highlighted an important non-developmental role for DNA methylation. Specifically, cognitive epigenetics has redefined DNA methylation as a highly plastic mechanism integral in mediating both the transcriptional activation and repression of genes essential for the process of learning and memory 6. Apart from cognitive epigenetics, studies modeling ischemic injury and neuropathic pain characterize DNA methylation as a labile mechanism that responds rapidly to a variety of CNS insults 7-9. In regards to astrocytes, several lines of evidence suggest DNA methylation plays an important role in astrogliogenesis. Fan et al., found that conditional KO of DNMT1 in neural progenitor cells (NPCs) resulted in precocious development of astrocytes concordant with a global state of hypomethylation 10. Additionally, Perisic et al., concluded differential levels of DNA methylation of the GLT-1 promoter mediated differential levels of expression of the glutamate transporter in the cortex and cerebellum, emphasizing a role in DNA methylation in establishing brain-region specific patterns of astrocytic gene expression 11. Overall, numerous studies underscore the dynamic and labile nature of DNA methylation in the CNS as environment, drugs, and injury have all been shown to change DNA methylation and often, gene expression 4,9. Together, these neuroepigenetic studies point to DNA methylation as a feasible therapeutic target with the potential to mitigate a variety of CNS pathologies.
As the field of epigenetics expands its understanding of the role of DNA methylation in neurodevelopment and disease, the challenge of moving DNA methylation towards a therapeutic target is performing not only correlative, but causative studies that define specific gene targets and sites. Additionally, surveying changes in DNA methylation specific to brain region and cell type remains an ongoing and time worthy challenge unique to the field of neuroepigenetics. This protocol utilizes a variety of techniques including fluorescence-activated cell sorting (FACS) of astrocytes, methylation-sensitive high resolution melt analysis (MS-HRM), and a methylation luciferase assay to investigate the DNA methylation status of KCNJ10, a gene that encodes for Kir4.1. Kir4.1 is a glial specific potassium channel that demonstrates both brain region and cell specific patterns of expression in the CNS 12-16. Kir4.1 expression increases moving from rostral to caudal CNS regions, with the highest expression occurring in the spinal cord 15. Although the channel is expressed in ependymal cells, oligodendrocytes and their precursor cells, Kir4.1 is predominantly expressed in astrocytes and thought to be essential for maintaining homeostatic levels of potassium as well as supporting glutamate uptake by setting the astrocytic resting membrane potential at a hyperpolarized -80mV 12,16-19. Importantly, the expression of Kir4.1 is non-static both during development and following multiple forms of CNS injury 20-25. We wished to examine the epigenetic regulation of this channel, specifically in astrocytes during development. The techniques utilized offer gene-specific and targeted CpG site analyses that provide causal evidence for a role of DNA methylation in regulating KCNJ10 gene expression. These techniques can be applied to other genes.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Papain Dissociation System</td>
			<td>Worthington Biochemical Corporation</td>
			<td>LK003150</td>
			<td></td>
		</tr>
		<tr>
			<td>AllPrep DNA/RNA Mini Kit</td>
			<td>Qiagen</td>
			<td>80204</td>
			<td></td>
		</tr>
		<tr>
			<td>Methyl Primer</td>
			<td>Applied Biosystems</td>
			<td>online</td>
			<td>software to localize CpG Islands</td>
		</tr>
		<tr>
			<td>EZ DNA methylation Kit</td>
			<td>Zymo Research</td>
			<td>D5001</td>
			<td></td>
		</tr>
		<tr>
			<td>Rat Premixed Calibration Standard</td>
			<td>EpiGenDx</td>
			<td>80-8060R-Premix</td>
			<td></td>
		</tr>
		<tr>
			<td>CpG Methylase (M.Sssl)</td>
			<td>Zymo Research</td>
			<td>E2010</td>
			<td></td>
		</tr>
		<tr>
			<td>QIAquick Gel Extraction&#160;</td>
			<td>QIagen</td>
			<td>28704</td>
			<td>Used for gel extraction and DNA cleanup</td>
		</tr>
		<tr>
			<td>Restriction enzymes</td>
			<td>New England BioLabs</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>NEB cutter</td>
			<td>New England BioLabs</td>
			<td>online</td>
			<td>verify restriction digest sites</td>
		</tr>
		<tr>
			<td>Dual Luciferase Reporter Assay System</td>
			<td>Promega</td>
			<td>E1910</td>
			<td></td>
		</tr>
		<tr>
			<td>Luc2 vector, pGL4.10</td>
			<td>Promega</td>
			<td>E6651</td>
			<td></td>
		</tr>
		<tr>
			<td>renilla vector, pGL4.74</td>
			<td>Promega</td>
			<td>E2241</td>
			<td></td>
		</tr>
		<tr>
			<td>TD-20/20 Luminometer</td>
			<td>Turner Designs</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Lipofectamine LTX and Plus Reagent</td>
			<td>Life Technologies</td>
			<td>A12621</td>
			<td></td>
		</tr>
		<tr>
			<td>Phenol, saturated pH 6.6/6.9</td>
			<td>Fisher Scientific</td>
			<td>BP 17501-100</td>
			<td></td>
		</tr>
		<tr>
			<td>Nanodrop 2000/2000c Spectrophtometer</td>
			<td>ThermoScientific</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>MeltDoctor Master Mix</td>
			<td>Life Technologies</td>
			<td>4415440</td>
			<td></td>
		</tr>
		<tr>
			<td>High Resolution Melt (HRM) Software v2.0</td>
			<td>Life Technologies</td>
			<td>4397808</td>
			<td></td>
		</tr>
		<tr>
			<td>AB SDS software v2.3</td>
			<td>Life Technologies</td>
			<td>online</td>
			<td></td>
		</tr>
		<tr>
			<td>AB High Resolution Melting Getting Started Guide&#160;</td>
			<td>Life Technologies</td>
			<td>online</td>
			<td></td>
		</tr>
		<tr>
			<td>AB 7900HT Fast Real-Time System</td>
			<td>Life Technologies</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

correlating gene-specific dna methylation changes with expression and transcriptional activity of astrocytic kcnj10 (kir4.1)

DNA methylation serves to regulate gene expression through the covalent attachment of a methyl group onto the C5 position of a cytosine in a cytosine-guanine dinucleotide. While DNA methylation provides long-lasting and stable changes in gene expression, patterns and levels of DNA methylation are also subject to change based on a variety of signals and stimuli. As such, DNA methylation functions as a powerful and dynamic regulator of gene expression. The study of neuroepigenetics has revealed a variety of physiological and pathological states that are associated with both global and gene-specific changes in DNA methylation. Specifically, striking correlations between changes in gene expression and DNA methylation exist in neuropsychiatric and neurodegenerative disorders, during synaptic plasticity, and following CNS injury. However, as the field of neuroepigenetics continues to expand its understanding of the role of DNA methylation in CNS physiology, delineating causal relationships in regards to changes in gene expression and DNA methylation are essential. Moreover, in regards to the larger field of neuroscience, the presence of vast region and cell-specific differences requires techniques that address these variances when studying the transcriptome, proteome, and epigenome. Here we describe FACS sorting of cortical astrocytes that allows for subsequent examination of a both RNA transcription and DNA methylation. Furthermore, we detail a technique to examine DNA methylation, methylation sensitive high resolution melt analysis (MS-HRMA) as well as a luciferase promoter assay. Through the use of these combined techniques one is able to not only explore correlative changes between DNA methylation and gene expression, but also directly assess if changes in the DNA methylation status of a given gene region are sufficient to affect transcriptional activity.

성상 세포의 풍부한 인구는 eGFP는-S100β 형질 전환 동물 (27)의 FACS 정렬을 통해 인수되었다. 때문에 P0-P40 세 세포와 출생 후 하루 50 (P50)보다 오래된 동물에서 분리 된 분자 분자, 동물의 품질을 감소 그러한 실험에 최적이다. 대뇌 피질 조직을 다음 실험에 사용 하였다. 2-6 동물의 피질 함께 모았다. FACS는 UAB 종합 유동 세포 계측법 핵심 시설에서 수행되었다. 정렬은 벡톤 디킨슨 (Becton Dickins...

Watch this Scientific Journal Video about Correlating Gene-specific DNA Methylation Changes with Expression and Transcriptional Activity of Astrocytic KCNJ10 Kir4.1 at JoVE.com

Correlating Gene-specific DNA Methylation Changes with Expression and Transcriptional Activity of Astrocytic KCNJ10 Kir4.1

DNA methylation is capable of maintaining stable levels of gene expression as well as allowing for dynamic changes in gene expression in response to a variety of stimuli. We detail techniques that allow the study of gene-specific changes in DNA methylation and the effect of these changes on gene expression.

유전자 특이 발현과 DNA 메틸화 변화와 성상 세포의 전사 활동의 상관 관계<em&gt; KCNJ10</em&gt; (Kir4.1)

DNA methylation serves to regulate gene expression through the covalent attachment of a methyl group onto the C5 position of a cytosine in a ...

correlating-gene-specific-dna-methylation-changes-with-expression

Research

JoVE Journal

Biology

Correlating Gene-specific DNA Methylation Changes with Expression and Transcriptional Activity of Astrocytic KCNJ10 (Kir4.1)

7.9K 조회수.  University of Alabama at Birmingham. DNA methylation is capable of maintaining stable levels of gene expression as well as allowing for dynamic changes in gene expression in response to a variety of stimuli. We detail techniques that allow the study of gene-specific changes in DNA methylation and the effect of these changes on gene expression. 

비디오: Correlating Gene-specific DNA Methylation Changes with Expression and Transcriptional Activity of Astrocytic KCNJ10 Kir4.1

Staining of Proteins in Gels with Coomassie G-250 without Organic Solvent and Acetic Acid

In classical protein staining protocols using Coomassie Brilliant Blue (CBB), solutions with high contents of toxic and flammable organic solvents (Methanol, Ethanol or 2-Propanol) and acetic acid are used for fixation, staining and destaining of proteins in a gel after SDS-PAGE. To speed up the procedure, heating the staining solution in the microwave oven for a short time is frequently used. This usually results in evaporation of toxic or hazardous Methanol, Ethanol or 2-Propanol and a strong smell of acetic acid in the lab which should be avoided due to safety considerations. In a protocol originally published in two patent applications by E.M. Wondrak (US2001046709 (A1), US6319720 (B1)), an alternative composition of the staining solution is described in which no organic solvent or acid is used. The CBB is dissolved in bidistilled water (60-80mg of CBB G-250 per liter) and 35 mM HCl is added as the only other compound in the staining solution. The CBB staning of the gel is done after SDS-PAGE and thorough washing of the gel in bidistilled water. By heating the gel during the washing and staining steps, the process can be finished faster and no toxic or hazardous compunds are evaporating. The staining of proteins occurs already within 1 minute after heating the gel in staining solution and is fully developed after 15-30 min with a slightly blue background that is destained completely by prolonged washing of the stained gel in bidistilled water, without affecting the stained protein bands.

A short protocol for protein staining with Coomassie Brilliant Blue (CBB) G-250 in polyacrylamide gels is described without using organic solvents or acetic acid as in the classical staining procedures with CBB.

유기 용매 및 초산없이 쿠매시 G - 250로 젤의 단백질 염색법

In classical protein staining protocols using Coomassie Brilliant Blue (CBB), solutions with high contents of toxic and flammable organic solvents ...

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생물학

Using the Gene Pulser MXcell Electroporation System to Transfect Primary Cells with High Efficiency

It is becoming increasingly apparent that electroporation is the most effective way to introduce plasmid DNA or siRNA into primary cells. The Gene Pulser MXcell electroporation system and Gene Pulser electroporation buffer (Bio-Rad) were specifically developed to easily transfect nucleic acids into mammalian cells and difficult-to-transfect cells, such as primary and stem cells. We will demonstrate how to perform a simple experiment to quickly identify the best electroporation conditions. We will demonstrate how to run several samples through a range of electroporation conditions so that an experiment can be conducted at the same time as optimization is performed. We will also show how optimal conditions identified using 96-well electroporation plates can be used with standard electroporation cuvettes, facilitating the switch from electroporation plates to electroporation cuvettes while maintaining the same electroporation efficiency. In the video, we will also discuss some of the key factors that can lead to the success or failure of electroporation experiments.

This procedure shows how to use the Gene Pulser MXcell electroporation system to rapidly and easily identify the best electroporation conditions for mouse embryonic fibroblasts (MEFs) or other primary cells. Considerations for troubleshooting are also discussed in the associated video.

고효율 기본 셀을 Transfect하는 진 Pulser Electroporation MXcell의 시스템을 사용하여

It is becoming increasingly apparent that electroporation is the most effective way to introduce plasmid DNA or siRNA into primary cells. The Gene Pulser ...

Using an Automated Cell Counter to Simplify Gene Expression Studies: siRNA Knockdown of IL-4 Dependent Gene Expression in Namalwa Cells

The use of siRNA mediated gene knockdown is continuing to be an important tool in studies of gene expression.  siRNA studies are being conducted not only to study the effects of downregulating single genes, but also to interrogate signaling pathways and other complex interaction networks.  These pathway analyses require both the use of relevant cellular models and methods that cause less perturbation to the cellular physiology.  Electroporation is increasingly being used as an effective way to introduce siRNA and other nucleic acids into difficult to transfect cell lines and primary cells without altering the signaling pathway under investigation. There are multiple critical steps to a successful siRNA experiment, and there are ways to simplify the work while improving the data quality at several experimental stages.  To help you get started with your siRNA mediated gene knockdown project, we will demonstrate how to perform a pathway study complete from collecting and counting the cells prior to electroporation through post transfection real-time PCR gene expression analysis.  The following study investigates the role of the transcriptional activator STAT6 in IL-4 dependent gene expression of CCL17 in a Burkitt lymphoma cell line (Namalwa).  The techniques demonstrated are useful for a wide range of siRNA-based experiments on both adherent and suspension cells.  We will also show how to streamline cell counting with the TC10 automated cell counter, how to electroporate multiple samples simultaneously using the MXcell electroporation system, and how to simultaneously assess RNA quality and quantity with the Experion automated electrophoresis system.

This procedure describes a quick and easy workflow to introduce siRNA into difficult to transfect cell lines and follow gene expression by real-time PCR. Use of an automated cell counter, multi-well electroporation plate, and automated electrophoresis station provide quick and reliable results without the need for expensive robotic handling.

유전자 발현 연구를 단순화하는 자동 셀 카운터를 사용하여 : Namalwa 셀에서 IL - 4 종속 유전자 발현의 siRNA의 최저

The use of siRNA mediated gene knockdown is continuing to be an important tool in studies of gene expression.  siRNA studies are being conducted not only ...

Determination of DNA Methylation of Imprinted Genes in Arabidopsis Endosperm

Arabidopsis thaliana is an excellent model organism for studying epigenetic mechanisms. One of the reasons is the loss-of-function null mutant of DNA methyltransferases is viable, thus providing a system to study how loss of DNA methylation in a genome affects growth and development. Imprinting refers to differential expression of maternal and paternal alleles and plays an important role in reproduction development in both mammal and plants. DNA methylation is critical for determining whether the maternal or paternal alleles of an imprinted gene is expressed or silenced. In flowering plants, there is a double fertilization event in reproduction: one sperm cell fertilizes the egg cell to form embryo and a second sperm fuses with the central cell to give rise to endosperm. Endosperm is the tissue where imprinting occurs in plants. MEDEA, a SET domain Polycomb group gene, and FWA, a transcription factor regulating flowering, are the first two genes shown to be imprinted in endosperm and their expression is controlled by DNA methylation and demethylation in plants. In order to determine imprinting status of a gene and methylation pattern in endosperm, we need to be able to isolate endosperm first. Since seed is tiny in Arabidopsis, it remains challenging to isolate Arabidopsis endosperm and examine its methylation. In this video protocol, we report how to conduct a genetic cross, to isolate endosperm tissue from seeds, and to determine the methylation status by bisulfite sequencing.

Determination of DNA Methylation of Imprinted Genes in Arabidopsis Endosperm

Imprinting is a phenomenon in plant and mammal reproduction. DNA methylation plays an important role in mechanisms of imprinting. Isolating endosperm and determining methylation status of imprinted genes in Arabidopsis can be difficult. In this protocol, we describe how to isolate endosperm and determine methylation by bisulfite sequencing.

에 각인 유전자의 DNA Methylation의 결정 Arabidopsis 배젖

Arabidopsis thaliana is an excellent model organism for studying epigenetic mechanisms. One of the reasons is the loss-of-function null mutant of DNA ...

DNA Methylation: Bisulphite Modification and Analysis

Epigenetics describes the heritable changes in gene function that occur independently to the DNA sequence. The molecular basis of epigenetic gene regulation is complex, but essentially involves modifications to the DNA itself or the proteins with which DNA associates. The predominant epigenetic modification of DNA in mammalian genomes is methylation of cytosine nucleotides (5-MeC). DNA methylation provides instruction to gene expression machinery as to where and when the gene should be expressed. The primary target sequence for DNA methylation in mammals is 5'-CpG-3' dinucleotides (Figure 1). CpG dinucleotides are not uniformly distributed throughout the genome, but are concentrated in regions of repetitive genomic sequences and CpG "islands" commonly associated with gene promoters (Figure 1). DNA methylation patterns are established early in development, modulated during tissue specific differentiation and disrupted in many disease states including cancer. To understand the biological role of DNA methylation and its role in human disease, precise, efficient and reproducible methods are required to detect and quantify individual 5-MeCs.
This protocol for bisulphite conversion is the "gold standard" for DNA methylation analysis and facilitates identification and quantification of DNA methylation at single nucleotide resolution. The chemistry of cytosine deamination by sodium bisulphite involves three steps (Figure 2). (1) Sulphonation: The addition of bisulphite to the 5-6 double bond of cytosine (2) Hydrolic Deamination: hydrolytic deamination of the resulting cytosine-bisulphite derivative to give a uracil-bisulphite derivative (3) Alkali Desulphonation: Removal of the sulphonate group by an alkali treatment, to give uracil. Bisulphite preferentially deaminates cytosine to uracil in single stranded DNA, whereas 5-MeC, is refractory to bisulphite-mediated deamination. Upon PCR amplification, uracil is amplified as thymine while 5-MeC residues remain as cytosines, allowing methylated CpGs to be distinguished from unmethylated CpGs by presence of a cytosine "C" versus thymine "T" residue during sequencing.
DNA modification by bisulphite conversion is a well-established protocol that can be exploited for many methods of DNA methylation analysis. Since the detection of 5-MeC by bisulphite conversion was first demonstrated by Frommer et al.1 and Clark et al.2, methods based around bisulphite conversion of genomic DNA account for the majority of new data on DNA methylation. Different methods of post PCR analysis may be utilized, depending on the degree of specificity and resolution of methylation required. Cloning and sequencing is still the most readily available method that can give single nucleotide resolution for methylation across the DNA molecule.

The gold standard for DNA methylation analysis is genomic sequencing of bisulphite converted DNA. This method takes advantage of the increased sensitivity of cytosine compared with 5-methylcytosine (5-MeC) to bisulphite deamination under acidic conditions. Unmethylated cytosines can be distinguished from methylated cytosines after PCR amplification of the target genomic DNA.

의 DNA Methylation : Bisulphite의 변경 및 분석

Epigenetics describes the heritable changes in gene function that occur independently to the DNA sequence. The molecular basis of epigenetic gene ...

Single Cell Transcriptional Profiling of Adult Mouse Cardiomyocytes

While numerous studies have examined gene expression changes from homogenates of heart tissue, this prevents studying the inherent stochastic variation between cells within a tissue. Isolation of pure cardiomyocyte populations through a collagenase perfusion of mouse hearts facilitates the generation of single cell microarrays for whole transcriptome gene expression, or qPCR of specific targets using nanofluidic arrays. We describe here a procedure to examine single cell gene expression profiles of cardiomyocytes isolated from the heart. This paradigm allows for the evaluation of metrics of interest which are not reliant on the mean (for example variance between cells within a tissue) which is not possible when using conventional whole tissue workflows for the evaluation of gene expression (Figure 1). We have achieved robust amplification of the single cell transcriptome yielding micrograms of double stranded cDNA that facilitates the use of microarrays on individual cells. In the procedure we describe the use of NimbleGen arrays which were selected for their ease of use and ability to customize their design. Alternatively, a reverse transcriptase - specific target amplification (RT-STA) reaction, allows for qPCR of hundreds of targets by nanofluidic PCR. Using either of these approaches, it is possible to examine the variability of expression between cells, as well as examining expression profiles of rare cell types from within a tissue. Overall, the single cell gene expression approach allows for the generation of data that can potentially identify idiosyncratic expression profiles that are typically averaged out when examining expression of millions of cells from typical homogenates generated from whole tissues.

Single cell expression profiling allows the detailed gene expression analysis of individual cells. We describe methods for the isolation of cardiomyocytes, and preparing the resulting lysates for either whole transcriptome microarray or qPCR of specific targets.

성인 마우스 Cardiomyocytes의 단세포 Transcriptional 프로파일

While numerous studies have examined gene expression changes from homogenates of heart tissue, this prevents studying the inherent stochastic variation ...

A Quantitative Assay to Study Protein:DNA Interactions, Discover Transcriptional Regulators of Gene Expression, and Identify Novel Anti-tumor Agents

Many DNA-binding assays such as electrophoretic mobility shift assays (EMSA), chemiluminescent assays, chromatin immunoprecipitation (ChIP)-based assays, and multiwell-based assays are used to measure transcription factor activity. However, these assays are nonquantitative, lack specificity, may involve the use of radiolabeled oligonucleotides, and may not be adaptable for the screening of inhibitors of DNA binding. On the other hand, using a quantitative DNA-binding enzyme-linked immunosorbent assay (D-ELISA) assay, we demonstrate nuclear protein interactions with DNA using the RUNX2 transcription factor that depend on specific association with consensus DNA-binding sequences present on biotin-labeled oligonucleotides. Preparation of cells, extraction of nuclear protein, and design of double stranded oligonucleotides are described. Avidin-coated 96-well plates are fixed with alkaline buffer and incubated with nuclear proteins in nucleotide blocking buffer. Following extensive washing of the plates, specific primary antibody and secondary antibody incubations are followed by the addition of horseradish peroxidase substrate and development of the colorimetric reaction. Stop reaction mode or continuous kinetic monitoring were used to quantitatively measure protein interaction with DNA. We discuss appropriate specificity controls, including treatment with non-specific IgG or without protein or primary antibody. Applications of the assay are described including its utility in drug screening and representative positive and negative results are discussed.

We developed a quantitative DNA-binding, ELISA-based assay to measure transcription factor interactions with DNA. High specificity for the RUNX2 protein was achieved with a consensus DNA-recognition oligonucleotide and specific monoclonal antibody. Colorimetric detection with an enzyme-coupled antibody substrate reaction was monitored in real time.

유전자 발현의 DNA 상호 작용, 디스 전사 레귤레이터, 그리고 소설 안티 종양 에이전트를 식별 : 단백질을 연구하는 정량 분석

Many DNA-binding assays such as electrophoretic mobility shift assays (EMSA), chemiluminescent assays, chromatin immunoprecipitation (ChIP)-based assays, ...

In vitro Methylation Assay to Study Protein Arginine Methylation

Protein arginine methylation is one of the most abundant post-translational modifications in the nucleus. Protein arginine methylation can be identified and/or determined via proteomic approaches, and/or immunoblotting with methyl-arginine specific antibodies. However, these techniques sometimes can be misleading and often provide false positive results. Most importantly, these techniques cannot provide direct evidence in support of the PRMT substrate specificity. In vitro methylation assays, on the other hand, are useful biochemical assays, which are sensitive, and consistently reveal if the identified proteins are indeed PRMT substrates. A typical in vitro methylation assay includes purified, active PRMTs, purified substrate and a radioisotope labeled methyl donor (S-adenosyl-L-[methyl-3H] methionine). Here we describe a step-by-step protocol to isolate catalytically active PRMT1, a ubiquitously expressed PRMT family member. The methyl transferase activities of the purified PRMT1 were later tested on Ras-GTPase activating protein binding protein 1 (G3BP1), a known PRMT substrate, in the presence of S-adenosyl-L-[methyl-3H] methionine as the methyl donor. This protocol can be employed not only for establishing the methylation status of novel physiological PRMT1 substrates, but also for understanding the basic mechanism of protein arginine methylation.

In vitro Methylation Assay to Study Protein Arginine Methylation

Protein arginine methylation, catalyzed by a class of enzymes viz., protein arginine methyl transferases (PRMTs), is the process of enzymatic addition of methyl group(s) to arginines within proteins. The in vitro methylation assay is the most dependable tool for assessing the methylation status of known or novel PRMT substrates.

체외 메틸화 분석에서 단백질 아르기닌 메틸화를 공부합니다

Protein arginine methylation is one of the most abundant post-translational modifications in the nucleus. Protein arginine methylation can be identified ...

Enhanced Reduced Representation Bisulfite Sequencing for Assessment of DNA Methylation at Base Pair Resolution

DNA methylation pattern mapping is heavily studied in normal and diseased tissues. A variety of methods have been established to interrogate the cytosine methylation patterns in cells. Reduced representation of whole genome bisulfite sequencing was developed to detect quantitative base pair resolution cytosine methylation patterns at GC-rich genomic loci. This is accomplished by combining the use of a restriction enzyme followed by bisulfite conversion. Enhanced Reduced Representation Bisulfite Sequencing (ERRBS) increases the biologically relevant genomic loci covered and has been used to profile cytosine methylation in DNA from human, mouse and other organisms. ERRBS initiates with restriction enzyme digestion of DNA to generate low molecular weight fragments for use in library preparation. These fragments are subjected to standard library construction for next generation sequencing. Bisulfite conversion of unmethylated cytosines prior to the final amplification step allows for quantitative base resolution of cytosine methylation levels in covered genomic loci. The protocol can be completed within four days. Despite low complexity in the first three bases sequenced, ERRBS libraries yield high quality data when using a designated sequencing control lane. Mapping and bioinformatics analysis is then performed and yields data that can be easily integrated with a variety of genome-wide platforms. ERRBS can utilize small input material quantities making it feasible to process human clinical samples and applicable in a range of research applications. The video produced demonstrates critical steps of the ERRBS protocol.

Enhanced Reduced Representation Bisulfite Sequencing is a method for the preparation of sequencing libraries for DNA methylation analysis based on restriction enzyme digestion combined with cytosine bisulfite conversion. This protocol requires 50 ng of starting material and yields base pair resolution data at GC-rich genomic regions.

자료 쌍 해상도에서 DNA 메틸화의 평가에 대한 표현 바이 설 파이트 시퀀싱을 감소 향상

DNA methylation pattern mapping is heavily studied in normal and diseased tissues. A variety of methods have been established to interrogate the cytosine ...

Targeted DNA Methylation Analysis by Next-generation Sequencing

The role of epigenetic processes in the control of gene expression has been known for a number of years. DNA methylation at cytosine residues is of particular interest for epigenetic studies as it has been demonstrated to be both a long lasting and a dynamic regulator of gene expression. Efforts to examine epigenetic changes in health and disease have been hindered by the lack of high-throughput, quantitatively accurate methods. With the advent and popularization of next-generation sequencing (NGS) technologies, these tools are now being applied to epigenomics in addition to existing genomic and transcriptomic methodologies. For epigenetic investigations of cytosine methylation where regions of interest, such as specific gene promoters or CpG islands, have been identified and there is a need to examine significant numbers of samples with high quantitative accuracy, we have developed a method called Bisulfite Amplicon Sequencing (BSAS). This method combines bisulfite conversion with targeted amplification of regions of interest, transposome-mediated library construction and benchtop NGS. BSAS offers a rapid and efficient method for analysis of up to 10 kb of targeted regions in up to 96 samples at a time that can be performed by most research groups with basic molecular biology skills. The results provide absolute quantitation of cytosine methylation with base specificity. BSAS can be applied to any genomic region from any DNA source. This method is useful for hypothesis testing studies of target regions of interest as well as confirmation of regions identified in genome-wide methylation analyses such as whole genome bisulfite sequencing, reduced representation bisulfite sequencing, and methylated DNA immunoprecipitation sequencing.

Bisulfite amplicon sequencing (BSAS) is a method for quantifying cytosine methylation in targeted genomic regions of interest. This method uses bisulfite conversion paired with PCR amplification of target regions prior to next-generation sequencing to produce absolute quantitation of DNA methylation at a base-specific level.

DNA 메틸화 분석 차세대 시퀀싱 대상

The role of epigenetic processes in the control of gene expression has been known for a number of years. DNA methylation at cytosine residues is of ...