This work was supported by National Health and Medical Research Council (NHMRC) grants (Grant ID 1062383 and 1063646) awarded to HJN. EAL is supported by an Australian Postgraduate Award.

The authors have nothing to disclose.

분비 시스템, 세균 이펙터 단백질의 숙주 세포의 세포질에서 이러한 시스템의 전송은 많은 병원성 박테리아가 복제 성 고유 한 틈새 내에서 감염을 확립 이용하는 중요한 독성 성분이다. 많은 연구 그룹의 초점은 세균 이펙터 호스트 단백질 및 숙주 세포에서이 경로 이펙터가 영향 사이의 상호 작용을 조사했다. 매우 제한된 조사있는 경우 호스트 단백질 성공 세균 이펙터 전위 필요한 될 가능성?...

Coxiella burnetii의는 인수 공통 인체 감염 Q 열병을 일으키는 독특한 세포 내 병원균이다. 이 질환은 증상이 혈청에서 종종 노출 한 후 심내막염 년으로 나타난다 생명을 위협하는 만성 감염 연장 임상 프레 젠 테이션의 광범위한 스펙트럼과 연결됩니다. 인간의 감염은 주로 반추 동물, 특히 젖소, 양, 염소 감염의 주요 저수지와 오염 된 에어로졸의 흡입을 통해 발생합니다. 이러한 동물 Coxiella 감염은 일반적으로 무증상이지만 감염 낙태를 트리거 할 수 있으며, 유체 출산 및 태반 내의 상당한 세균 부하는 한 로컬 환경을 오염시킬 수있다. 공중 보건과 농업 산업 모두 최근 네덜란드 2에서 발생한 Q 열병 발생이 관찰되었다에 엄청난 부담 등 오염의 예는 수 있습니다. 2007 년과 사이2010, Q 열병 4,000 통해 인간의 경우는 진단받은이 발발은 염소 농장 3의 중요한 오염에 연결되었다. 또한, Coxiella 인해 심각한 이환율과 사망률 (4)을 일으킬 수있는 박테리아와 필요한 낮은 전염성 선량의 환경 안정성에 미국 질병 통제 예방 센터에 의해 분류로, 잠재적 인 생물학적 무기입니다. Coxiella은 두 단계에 존재하는 천연 소스에서 고립 된 단계 I 생물은 매우 악성이며, 단계 II 생물이 높은 생체 내에서 감쇠된다. 예를 들어, Coxiella burnetii 나인 마일 단계 I 생물의 여러 체외 통로 후, 단계 II 박테리아가 절단 된 리포 폴리 사카 라이드의 결과로 돌이킬 수없는 염색체 삭제를 포함하는 제조 하였다 (LPS) 5. 이 균주, C. burnetii NMII는 조직 배양 모델 I, 위상 표현형 유사하고 안전한 모드를 제공한다연구진은 실험실 5 Coxiella의 발병 기전을 연구하기위한 리터. 최근 몇 년 동안 몇 가지 혁신이 빠르게 Coxiella 유전학의 분야를 전진했다. 특히, 무균 매체의 개발 (시트르산 시스테인 매체 산성화 - ACCM-2)는 모두 액체 및 고체 배지에 6,7 Coxiella의 무 세포 성장을 허용했다. 이것은 유도 유전자 발현 시스템, 셔틀 벡터 및 랜덤 트랜스포존 시스템 8-11 포함 Coxiella 가능한 유전 도구 직접 개선 결과. 가장 최근에, 대상 유전자의 불 활성화에 대한 두 가지 방법이 특정 독성 유전자 후보 (12)를 조사하기위한 방법을 포장, 개발되었다. 폐포 대 식세포에 의해 내재화 이어 Coxiella는 막 결합 구획 내에 높은 번호에 복제는 액포 (CCV)을 함유 Coxiella- 불린다. CCV는 호스트 세포 내 이입 매매 일이 필요합니다거친 초기와 후기 엔도 좀이 리소좀 유래 세포 기관 (13)에 성숙 할 때까지. 이 과정을 통해 상기 CCV 중 하나가 일시적으로 나타나거나 포함 액포와 연관되지만 Rab5, Rab7, CD63 및 LAMP-1 13-15에 한정되지 유지 숙주 요인을 취득한다. 숙주 세포 내에서 Coxiella의 복제는 완전한 기능 도트 / ICM 형 IVB 분비 시스템 (T4SS) 8,16,17에 전적으로 의존한다. 이 분비 시스템 ancestrally 공액 시스템과 관련된 여러 단백질 구조 및 박테리아 단백질을 제공하기 위해 모두 세균과 액포 막에 걸쳐 호스트 세포질 18에, 이펙터 불린다. Coxiella T4SS는 기능적으로 레지오넬라 뉴모 필라 (19, 20)의 잘 특징 유형 IVB 점 / ICM 분비 시스템과 매우 유사합니다. Coxiella이 리소좀 유래 산성에 도달 할 때까지 흥미롭게 T4SS 이후 이펙터 전위의 활성화가 발생하지 않는다세포 기관, 약 8 시간 게시물 감염 17,21. 현재까지 130여 점 / ICM 이펙터는 9,17,22-24를 확인되었습니다. 이 이펙터의 대부분은 가능성이 숙주 세포 내에서 Coxiella의 복제시 중요한 역할을; 단, 약간의 이펙터 기능 25-29 특성화되었다. 본 연구에서 우리는 숙주 세포의 세포질 내 β-lactamase의 활성을 통해 (이하 BLAM 기판이라 함) CCF2-AM FRET 기판 (도 1)의 절단에 의존하는 형광 기반 전위 분석을 이용한다. 관심의 유전자는 구성 적 발현을 제공하는 리포터 플라스미드에 β-lactamase를 (연기하는거야)-1 TEM 융합된다. BLAM 기판을 FRET 쌍을 형성하는 두 개의 형광 발색단 (쿠마린 및 플루오 레세 인)로 구성되어있다. 플루 오레 신 및 이펙터 전위의 부재하에 녹색 형광 발광의 FRET의 쿠마린의 여기 결과; 그러나, 만약 즐M 이펙터 융합 단백질은 호스트 세포질로 전좌하고, 얻어진 β-lactamase의 활성을 절단 여진 다음 청색 형광 방출을 생산 FRET 쌍을 분리 BLA​​M 기판의 β 락탐 고리. 이 전위 분석이 잘 C. 등 다양한 세포 내 및 세포 외 박테리아의 범위에서 이펙터 단백질을 식별하는 방식으로 입증되었다 burnetii, L. 뉴모 필라, L. longbeachae, 클라미디아 트라코마 티스, 장내 유해 E. 대장균, 살모넬라 균 및 브루셀라 17,30-35. Coxiella 이펙터 전위 특정 숙주 인자의 역할을 결정하기 위해 우리는 특히 작은 간섭 RNA의 (siRNA의), RNA 간섭으로 알려진 유전자 침묵을위한 확립 된 방법을 이용한다. 원래 예쁜 꼬마 선충에서 발견, RNA 간섭은 타고난 defe에 사용되는 보존 내생 세포 과정바이러스에 대한 NSE뿐만 아니라 유전자 조절 (36, 37). 서열 - 특이 적 siRNA를 바인딩 한 후 mRNA를 분해 특정 유전자 침묵 또는 최저 38 결과 (RNA 유도 침묵 복합체) RISC 통해 발생한다. 이 연구에서의 siRNA가 세포 내 이입 경로의 중요한 레귤레이터 두 호스트 단백질 Rab5A 및 Rab7A를 대상으로 하였다. 이펙터 전위에 Rab5A 및 Rab7A 입을의 영향 C.을 사용하여 확인 하였다 burnetii pBlaM-CBU0077. 것은 이미 Coxiella 17 도트 / ICM 분비 시스템 전좌 것으로 나타났다 CBU0077로 선택 하였다. siRNA의 유전자 사일런 여기 기재된 fluorescencebased 전위 분석 양쪽을 이용하여 우리는 Coxiella 이펙터 단백질의 전위에 숙주 인자의 역할을 설정하기 시작한다. 이 방법은 유사한 secretio 소유 모두 세포 내 및 세포 외 박테리아의 넓은 범위에 적용될 수있다이펙터 단백질의 전위에 대한 책임 N 시스템.

<table border="0" cellpadding="0" cellspacing="0" width="760">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Reagents</td>
			<td style="width:87px;"></td>
			<td style="width:119px;"></td>
			<td style="width:211px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Citric acid</td>
			<td style="width:87px;">Sigma</td>
			<td style="width:119px;">C0759</td>
			<td style="width:211px;">ACCM-2 medium component</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Sodium citrate</td>
			<td style="width:87px;">Sigma</td>
			<td style="width:119px;">S4641</td>
			<td style="width:211px;">ACCM-2 medium component</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Potassium phosphate</td>
			<td style="width:87px;">Sigma</td>
			<td style="width:119px;">60218</td>
			<td style="width:211px;">ACCM-2 medium component</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Magnesium chloride</td>
			<td style="width:87px;">Calbiochem</td>
			<td style="width:119px;">442611</td>
			<td style="width:211px;">ACCM-2 medium component</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Calcium chloride</td>
			<td style="width:87px;">Sigma</td>
			<td style="width:119px;">C5080</td>
			<td style="width:211px;">ACCM-2 medium component</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Iron sulfate</td>
			<td style="width:87px;">Fisher</td>
			<td style="width:119px;">S93248</td>
			<td style="width:211px;">ACCM-2 medium component</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Sodium chloride</td>
			<td style="width:87px;">Sigma</td>
			<td style="width:119px;">S9625</td>
			<td style="width:211px;">ACCM-2 medium component</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">L-cysteine</td>
			<td style="width:87px;">Sigma</td>
			<td style="width:119px;">C6852</td>
			<td style="width:211px;">ACCM-2 medium component</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Bacto-neopeptone</td>
			<td style="width:87px;">BD</td>
			<td style="width:119px;">211681</td>
			<td style="width:211px;">ACCM-2 medium component</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Casamino acids</td>
			<td style="width:87px;">Fisher</td>
			<td style="width:119px;">BP1424</td>
			<td style="width:211px;">ACCM-2 medium component</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Methyl beta cyclodextrin</td>
			<td style="width:87px;">Sigma</td>
			<td style="width:119px;">C4555</td>
			<td style="width:211px;">ACCM-2 medium component</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:343px;">RPMI + Glutamax</td>
			<td style="width:87px;">ThermoFisher Scientific</td>
			<td style="width:119px;">61870-036</td>
			<td style="width:211px;">ACCM-2 medium component</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Chloramphenicol</td>
			<td style="width:87px;">Sigma</td>
			<td style="width:119px;">C0378</td>
			<td style="width:211px;">For bacterial culture</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">ON-TARGETplus Non-targeting Control Pool (OTP)</td>
			<td style="width:87px;">Dharmacon</td>
			<td style="width:119px;">D-001810-10-05</td>
			<td style="width:211px;">Non-targeting control</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:343px;">siGENOME Human PLK1 (5347) siRNA - SMARTpool</td>
			<td style="width:87px;">Dharmacon</td>
			<td style="width:119px;">M-003290-01-005</td>
			<td style="width:211px;">Causes cell death; measure of transfection efficiency</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">siGENOME Human RAB5A (5968) siRNA - SMARTpool</td>
			<td style="width:87px;">Dharmacon</td>
			<td style="width:119px;">M-004009-00-0005</td>
			<td style="width:211px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">siGENOME Human RAB7A (7879) siRNA - SMARTpool</td>
			<td style="width:87px;">Dharmacon</td>
			<td style="width:119px;">M-010388-00-0005</td>
			<td style="width:211px;"></td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:343px;">5X siRNA buffer</td>
			<td style="width:87px;">Dharmacon</td>
			<td style="width:119px;">B-002000-UB-100</td>
			<td style="width:211px;">Use sterile RNase-free water to dilute 5X siRNA buffer to 1X siRNA buffer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">DharmaFECT-1 Transfection Reagent</td>
			<td style="width:87px;">Dharmacon</td>
			<td style="width:119px;">T-2001-01</td>
			<td style="width:211px;">For transfection</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:343px;">Opti-MEM + GlutaMAX</td>
			<td style="width:87px;">ThermoFisher Scientific</td>
			<td style="width:119px;">51985-034</td>
			<td style="width:211px;">Reduced-serum medium used for transfection</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:343px;">DMEM + GlutaMAX</td>
			<td style="width:87px;">ThermoFisher Scientific</td>
			<td style="width:119px;">10567-014</td>
			<td style="width:211px;">For cell culture and infection</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:343px;">Heat-inactivated fetal calf serum (FCS)</td>
			<td style="width:87px;">Thermo Scientific</td>
			<td style="width:119px;">SH30071.03</td>
			<td style="width:211px;">Can use alternate equivalent product</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">DMSO</td>
			<td style="width:87px;">Sigma</td>
			<td style="width:119px;">D8418</td>
			<td style="width:211px;">For storage of Coxiella strain</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">PBS</td>
			<td style="width:87px;"></td>
			<td style="width:119px;"></td>
			<td style="width:211px;">For cell culture</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:343px;">0.05% Trypsin + EDTA</td>
			<td style="width:87px;">ThermoFisher Scientific</td>
			<td style="width:119px;">25300-054</td>
			<td style="width:211px;">For cell culture</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:343px;">dH2O</td>
			<td style="width:87px;"></td>
			<td style="width:119px;"></td>
			<td style="width:211px;">For dilution of samples and standards for qPCR</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:343px;">Quick-gDNA Mini Prep</td>
			<td style="width:87px;">ZYMO Research</td>
			<td style="width:119px;">D3007</td>
			<td style="width:211px;">Can use alternate equivalent product to extract gDNA</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:343px;">SensiFAST SYBR No-ROX Kit</td>
			<td style="width:87px;">Bioline</td>
			<td style="width:119px;">BIO-98020</td>
			<td style="width:211px;">Can use alternate equivalent qPCR master mix product for qPCR reaction</td>
		</tr>
		<tr height="120">
			<td height="120" style="height:120px;width:343px;">LiveBLAzer FRET-B/G Loading kit with CCF2-AM</td>
			<td style="width:87px;">Invitrogen</td>
			<td style="width:119px;">K1032</td>
			<td style="width:211px;">For measurement of translocation using fluorescence and generation of the 6X loading solution (contains Solution A, B, C and DMSO)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Sodium hydroxide</td>
			<td style="width:87px;">Merck</td>
			<td style="width:119px;">106469</td>
			<td style="width:211px;">Probenicid solution component</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Sodium phosphate monobasic</td>
			<td style="width:87px;">Sigma</td>
			<td style="width:119px;">71505</td>
			<td style="width:211px;">Probenicid solution component</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">di-Sodium hydrogen orthophosphate</td>
			<td style="width:87px;">Merck</td>
			<td style="width:119px;">106586</td>
			<td style="width:211px;">Probenicid solution component</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Probenicid</td>
			<td style="width:87px;">Sigma</td>
			<td style="width:119px;">P8761</td>
			<td style="width:211px;">Probenicid solution component</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:343px;">DRAQ5 Fluorescent Probe Solution (5 mM)</td>
			<td style="width:87px;">ThermoFisher Scientific</td>
			<td style="width:119px;">62251</td>
			<td style="width:211px;">Nuclei stain to determine cell viablity. Use 1:4000 diluted in PBS.&#160;</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:343px;">4% PFA (paraformaldehyde) solution in PBS</td>
			<td style="width:87px;">Sigma</td>
			<td style="width:119px;">P6148</td>
			<td style="width:211px;">Fixing solution for HeLa 229 cells</td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:343px;">25cm2 tissue culture flask with vented cap</td>
			<td style="width:87px;">Corning</td>
			<td style="width:119px;">430639</td>
			<td style="width:211px;">For growth of bacterial strain</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:343px;">96 Well Flat Clear bottom Black Polystyrene TC-Treated Microplates, Individually wrapped, with Lid, Sterile</td>
			<td style="width:87px;">Corning</td>
			<td style="width:119px;">3603</td>
			<td style="width:211px;"></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:343px;">75cm2 tissue culture flask with vented cap</td>
			<td style="width:87px;">Corning</td>
			<td style="width:119px;">430641</td>
			<td style="width:211px;">For growth of HeLa 229 cells</td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:343px;">175cm2 tissue culture flask with vented cap</td>
			<td style="width:87px;">Corning</td>
			<td style="width:119px;">431080</td>
			<td style="width:211px;">For growth of HeLa 229 cells</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Haemocytometer</td>
			<td style="width:87px;"></td>
			<td style="width:119px;"></td>
			<td style="width:211px;">For quantification of HeLa 229 cells</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Tear-A-Way 96 Well PCR plates</td>
			<td style="width:87px;">4titude</td>
			<td style="width:119px;">4ti-0750/TA</td>
			<td style="width:211px;">For qPCR reaction</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">8-Lid chain, flat</td>
			<td style="width:87px;">Sarstedt</td>
			<td style="width:119px;">65.989.002</td>
			<td style="width:211px;">For qPCR reaction</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Equipment</td>
			<td style="width:87px;"></td>
			<td style="width:119px;"></td>
			<td style="width:211px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Bench top microfuge</td>
			<td style="width:87px;"></td>
			<td style="width:119px;"></td>
			<td style="width:211px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Bench top vortex</td>
			<td style="width:87px;"></td>
			<td style="width:119px;"></td>
			<td style="width:211px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Orbital mixer</td>
			<td style="width:87px;"></td>
			<td style="width:119px;"></td>
			<td style="width:211px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Centrifuge</td>
			<td style="width:87px;">Eppendorf</td>
			<td style="width:119px;">5810 R</td>
			<td style="width:211px;">For pelleting bacterial culture</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:343px;">Nanodrop</td>
			<td style="width:87px;"></td>
			<td style="width:119px;"></td>
			<td style="width:211px;">For gDNA quantification</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:343px;">Mx3005P QPCR machine</td>
			<td style="width:87px;">Aligent Technologies</td>
			<td style="width:119px;">401456</td>
			<td style="width:211px;">For quantification of Coxiella genomes in 7 day culture</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:343px;">ClarioSTAR microplate reader</td>
			<td style="width:87px;">BMG LabTech</td>
			<td style="width:119px;"></td>
			<td style="width:211px;">For measurement of fluorescence</td>
		</tr>
	</tbody>
</table>

applying fluorescence resonance energy transfer (fret) to examine effector translocation efficiency by coxiella burnetii during sirna silencing

Coxiella burnetii의, Q 발열의 원인 물질은 복제 성 틈새를 확립 타입 IV 도트 / ICM 분비 시스템에 의존하여 세포 내 병원체이다. 이펙터의 코호트는 호스트 프로세스를 조작 및 복제에 대한 고유 리소좀 유래 액포의 확립을 허용하는 숙주 세포에 본 시스템을 통해 전좌된다. 특정 유전자의 siRNA를 이용하여 침묵과 β-lactamase의 활성에 의존하는 FRET 기반의 기판을 사용하여 이펙터 전위 측정 : 여기에 제시된 방법은 두 개의 잘 확립 된 기술의 조합을 포함한다. 이 두 접근 방법의 적용, 우리는 박테리아 분비 시스템 기능 및 이펙터 전위에서 호스트 인자의 역할을 이해하기 시작할 수있다. 이 연구에서 우리는 Rab5A과 Rab7A, 모두 세포 내 이입 인신 매매 경로의 중요한 규제 기관의 역할을 조사했다. 우리는 이펙터 translocatio의 감소 중 단백질 결과의 발현을 침묵 입증N 효율. 이러한 방법은 또한 쉽게 분비 시스템을 이용하는 다른 세포 및 세포 외 병원체를 조사하도록 변형 될 수있다. 이러한 방식으로, 세균 이펙터 전위에 관련된 호스트 요인 글로벌 영상이 드러날 수있다.

이 연구를 들면, C. CBU0077 이전 Coxiella 도트 / ICM 분비 시스템 (17)의 전좌 이펙터로 도시 된 바와 같이 burnetii pBlaM-CBU0077 균주를 선택 하였다. 앞서 감염, 칠일 C.의 게놈 / ㎖의 총 개수 burnetii pBlaM-CBU0077 배양 물을 사용 qPCR에 열거 하였다. (4)는 순환 액의 예를 보여주는 도표 (TR) 값은 다음의 두 qPCR에 표준 샘?...

Watch this Scientific Journal Video about Applying Fluorescence Resonance Energy Transfer FRET to Examine Effector Translocation Efficiency by Coxiella burnetii during siRNA Silencing at JoVE.com

Applying Fluorescence Resonance Energy Transfer FRET to Examine Effector Translocation Efficiency by Coxiella burnetii during siRNA Silencing

세균성 병원균과 호스트 사이의 상호 작용을 조사하는 것은 생물학적 연구의 중요한 영역입니다. 여기서는 BLAM 기판을 사용하여 siRNA의 유전자 사일런 동안 Coxiella burnetii에 의해 이펙터 전위를 측정하기 위해 필요한 기술들을 설명한다.

적용 형광 공명 에너지 전달 (FRET)을하여 이펙터 전좌 효율을 검사합니다<em&gt; Coxiella burnetii의</em&gt; siRNA를 음소거시

Coxiella burnetii, the causative agent of Q fever, is an intracellular pathogen that relies on a Type IV Dot/Icm Secretion System to establish a ...

applying-fluorescence-resonance-energy-transfer-fret-to-examine

Research

JoVE Journal

Immunology and Infection

Applying Fluorescence Resonance Energy Transfer (FRET) to Examine Effector Translocation Efficiency by Coxiella burnetii during siRNA Silencing

10.6K 조회수.  University of Melbourne.  세균성 병원균과 호스트 사이의 상호 작용을 조사하는 것은 생물학적 연구의 중요한 영역입니다. 여기서는 BLAM 기판을 사용하여 siRNA의 유전자 사일런 동안 Coxiella burnetii에 의해 이펙터 전위를 측정하기 위해 필요한 기술들을 설명한다. 

비디오: Applying Fluorescence Resonance Energy Transfer FRET to Examine Effector Translocation Efficiency by Coxiella burnetii during siRNA Silencing

Purification of Specific Cell Population by Fluorescence Activated Cell Sorting (FACS)

Experimental and clinical studies often require highly purified cell populations.  FACS is a technique of choice to purify cell populations of known phenotype.  Other bulk methods of purification include panning, complement depletion and magnetic bead separation.  However, FACS has several advantages over other available methods.  FACS is the preferred method when very high purity of the desired population is required, when the target cell population expresses a very low level of the identifying marker or when cell populations require separation based on differential marker density.  In addition, FACS is the only available purification technique to isolate cells based on internal staining or intracellular protein expression, such as a genetically modified fluorescent protein marker.  FACS allows the purification of individual cells based on size, granularity and fluorescence.  In order to purify cells of interest, they are first stained with fluorescently-tagged monoclonal antibodies (mAb), which recognize specific surface markers on the desired cell population (1).  Negative selection of unstained cells is also possible.  FACS purification requires a flow cytometer with sorting capacity and the appropriate software.  For FACS, cells in suspension are passed as a stream in droplets with each containing a single cell in front of a laser.  The fluorescence detection system detects cells of interest based on predetermined fluorescent parameters of the cells.  The instrument applies a charge to the droplet containing a cell of interest and an electrostatic deflection system facilitates collection of the charged droplets into appropriate collection tubes (2).  The success of staining and thereby sorting depends largely on the selection of the identifying markers and the choice of mAb.  Sorting parameters can be adjusted depending on the requirement of purity and yield.  Although FACS requires specialized equipment and personnel training, it is the method of choice for isolation of highly purified cell populations.

Purification of Specific Cell Population by Fluorescence Activated Cell Sorting FACS

For many scientific studies requiring a biological and chemical analysis of cell populations the cells must be in a high state of purity. Fluorescence activated cell sorting (FACS) is a superior method in which to obtain pure cell populations.

형광 활성 세포 정렬 (외과)에 의해 특정 세포 인구의 정제

Experimental and clinical studies often require highly purified cell populations.  FACS is a technique of choice to purify cell populations of known ...

연구

면역학 및 감염병학

Detection of Toxin Translocation into the Host Cytosol by Surface Plasmon Resonance

AB toxins consist of an enzymatic A subunit and a cell-binding B subunit1. These toxins are secreted into the extracellular milieu, but they act upon targets within the eukaryotic cytosol. Some AB toxins travel by vesicle carriers from the cell surface to the endoplasmic reticulum (ER) before entering the cytosol2-4. In the ER, the catalytic A chain dissociates from the rest of the toxin and moves through a protein-conducting channel to reach its cytosolic target5. The translocated, cytosolic A chain is difficult to detect because toxin trafficking to the ER is an extremely inefficient process: most internalized toxin is routed to the lysosomes for degradation, so only a small fraction of surface-bound toxin reaches the Golgi apparatus and ER6-12.

To monitor toxin translocation from the ER to the cytosol in cultured cells, we combined a subcellular fractionation protocol with the highly sensitive detection method of surface plasmon resonance (SPR)13-15. The plasma membrane of toxin-treated cells is selectively permeabilized with digitonin, allowing collection of a cytosolic fraction which is subsequently perfused over an SPR sensor coated with an anti-toxin A chain antibody. The antibody-coated sensor can capture and detect pg/mL quantities of cytosolic toxin. With this protocol, it is possible to follow the kinetics of toxin entry into the cytosol and to characterize inhibitory effects on the translocation event. The concentration of cytosolic toxin can also be calculated from a standard curve generated with known quantities of A chain standards that have been perfused over the sensor. Our method represents a rapid, sensitive, and quantitative detection system that does not require radiolabeling or other modifications to the target toxin.

In this report, we describe how surface plasmon resonance is used to detect toxin entry into the host cytosol. This highly sensitive method can provide quantitative data on the amount of cytosolic toxin, and it can be applied to a range of toxins.

표면 Plasmon 공명하여 호스트 Cytosol에 독소를 Translocation의 감지

AB toxins consist of an enzymatic A subunit and a cell-binding B subunit1.  These toxins are secreted into the extracellular milieu, but they act upon ...

Accelerated Type 1 Diabetes Induction in Mice by Adoptive Transfer of Diabetogenic CD4+ T Cells

The nonobese diabetic (NOD) mouse spontaneously develops autoimmune diabetes after 12 weeks of age and is the most extensively studied animal model of human Type 1 diabetes (T1D). Cell transfer studies in irradiated recipient mice have established that T cells are pivotal in T1D pathogenesis in this model. We describe herein a simple method to rapidly induce T1D by adoptive transfer of purified, primary CD4+ T cells from pre-diabetic NOD mice transgenic for the islet-specific T cell receptor (TCR) BDC2.5 into NOD.SCID recipient mice. The major advantages of this technique are that isolation and adoptive transfer of diabetogenic T cells can be completed within the same day, irradiation of the recipients is not required, and a high incidence of T1D is elicited within 2 weeks after T cell transfer. Thus, studies of pathogenesis and therapeutic interventions in T1D can proceed at a faster rate than with methods that rely on heterogenous T cell populations or clones derived from diabetic NOD mice.

We provide a reproducible method to induce type 1 diabetes (T1D) in mice within two weeks by the adoptive transfer of islet antigen-specific, primary CD4+ T cells.

Diabetogenic CD4의 입양 전송하여 마우스의 가속 제 1 형 당뇨병 유도 + T 세포

The nonobese diabetic (NOD) mouse spontaneously develops autoimmune diabetes after 12 weeks of age and is the most extensively studied animal model of ...

Induction of Murine Intestinal Inflammation by Adoptive Transfer of Effector CD4+CD45RBhigh T Cells into Immunodeficient Mice

There are many different animal models available for studying the pathogenesis of human inflammatory bowel diseases (IBD), each with its own advantages and disadvantages. We describe here an experimental colitis model that is initiated by adoptive transfer of syngeneic splenic CD4+CD45RBhigh T cells into T and B cell deficient recipient mice. The CD4+CD45RBhigh T cell population that largely consists of na&#239;ve effector cells is capable of inducing chronic intestinal inflammation, closely resembling key aspects of human IBD. This method can be manipulated to study aspects of disease onset and progression. Additionally it can be used to study the function of innate, adaptive, and regulatory immune cell populations, and the role of environmental exposures, i.e., the microbiota, in intestinal inflammation. In this article we illustrate the methodology for inducing colitis with a step-by-step protocol. This includes a video demonstration of key technical aspects required to successfully develop this murine model of experimental colitis for research purposes.

Induction of Murine Intestinal Inflammation by Adoptive Transfer of Effector CD4+CD45RBhigh T Cells into Immunodeficient Mice

Here, we present a protocol to induce colonic inflammation in mice by adoptive transfer of syngeneic CD4+CD45RBhigh T cells into T and B cell deficient recipients. Clinical and histopathological features mimic human inflammatory bowel diseases. This method allows the study of the initiation of colonic inflammation and progression of disease.

이펙터 CD4의 입양 전송하여 쥐과 장내 염증의 유도<sup&gt; +</sup&gt; CD45RB<sup&gt; 높은</sup&gt; 면역 결핍 마우스에게 T 세포

There are many different animal models available for studying the pathogenesis of human inflammatory bowel diseases (IBD), each with its own advantages ...

Generation and Multi-phenotypic High-content Screening of Coxiella burnetii Transposon Mutants

Invasion and colonization of host cells by bacterial pathogens depend on the activity of a large number of prokaryotic proteins, defined as virulence factors, which can subvert and manipulate key host functions. The study of host/pathogen interactions is therefore extremely important to understand bacterial infections and develop alternative strategies to counter infectious diseases. This approach however, requires the development of new high-throughput assays for the unbiased, automated identification and characterization of bacterial virulence determinants. Here, we describe a method for the generation of a GFP-tagged mutant library by transposon mutagenesis and the development of high-content screening approaches for the simultaneous identification of multiple transposon-associated phenotypes. Our working model is the intracellular bacterial pathogen Coxiellaburnetii, the etiological agent of the zoonosis Q fever, which is associated with severe outbreaks with a consequent health and economic burden. The obligate intracellular nature of this pathogen has, until recently, severely hampered the identification of bacterial factors involved in host pathogen interactions, making of Coxiella the ideal model for the implementation of high-throughput/high-content approaches.

Generation and Multi-phenotypic High-content Screening of Coxiella burnetii Transposon Mutants

Coxiella burnetii is an obligate intracellular Gram-negative bacterium responsible for the zoonotic disease Q fever. Here we describe methods for the generation of Coxiella fluorescent transposon mutants as well as the automated identification and analysis of the resulting internalization, replication and cytotoxic phenotypes.

세대와의 멀티 표현형 높은 콘텐츠 상영<em&gt; Coxiella burnetii의</em&gt; 트랜스포존 돌연변이

Invasion and colonization of host cells by bacterial pathogens depend on the activity of a large number of prokaryotic proteins, defined as virulence ...

Applying an Inducible Expression System to Study Interference of Bacterial Virulence Factors with Intracellular Signaling

The technique presented here allows one to analyze at which step a target protein, or alternatively a small molecule, interacts with the components of a signaling pathway. The method is based, on the one hand, on the inducible expression of a specific protein to initiate a signaling event at a defined and predetermined step in the selected signaling cascade. Concomitant expression, on the other hand, of the gene of interest then allows the investigator to evaluate if the activity of the expressed target protein is located upstream or downstream of the initiated signaling event, depending on the readout of the signaling pathway that is obtained. Here, the apoptotic cascade was selected as a defined signaling pathway to demonstrate protocol functionality. Pathogenic bacteria, such as Coxiella burnetii, translocate effector proteins that interfere with host cell death induction in the host cell to ensure bacterial survival in the cell and to promote their dissemination in the organism. The C. burnetii effector protein CaeB effectively inhibits host cell death after induction of apoptosis with UV-light or with staurosporine. To narrow down at which step CaeB interferes with the propagation of the apoptotic signal, selected proteins with well-characterized pro-apoptotic activity were expressed transiently in a doxycycline-inducible manner. If CaeB acts upstream of these proteins, apoptosis will proceed unhindered. If CaeB acts downstream, cell death will be inhibited. The test proteins selected were Bax, which acts at the level of the mitochondria, and caspase 3, which is the major executioner protease. CaeB interferes with cell death induced by Bax expression, but not by caspase 3 expression. CaeB, thus, interacts with the apoptotic cascade between these two proteins.

The method described here is used to induce the apoptotic signaling cascade at defined steps in order to dissect the activity of an anti-apoptotic bacterial effector protein. This method can also be used for inducible expression of pro-apoptotic or toxic proteins, or for dissecting interference with other signaling pathways.

유도 발현 시스템을 적용하면 세포 내 신호와 세균 독성 요인의 간섭을 연구하기 위해

The technique presented here allows one to analyze at which step a target protein, or alternatively a small molecule, interacts with the components of a ...

Analysis of Yersinia enterocolitica Effector Translocation into Host Cells Using Beta-lactamase Effector Fusions

Many gram-negative bacteria including pathogenic Yersinia spp. employ type III secretion systems to translocate effector proteins into eukaryotic target cells. Inside the host cell the effector proteins manipulate cellular functions to the benefit of the bacteria. To better understand the control of type III secretion during host cell interaction, sensitive and accurate assays to measure translocation are required. We here describe the application of an assay based on the fusion of a Yersinia enterocolitica effector protein fragment (Yersinia outer protein; YopE) with TEM-1 beta-lactamase for quantitative analysis of translocation. The assay relies on cleavage of a cell permeant FRET dye (CCF4/AM) by translocated beta-lactamase fusion. After cleavage of the cephalosporin core of CCF4 by the beta-lactamase, FRET from coumarin to fluorescein is disrupted and excitation of the coumarin moiety leads to blue fluorescence emission. Different applications of this method have been described in the literature highlighting its versatility. The method allows for analysis of translocation in vitro and also in in vivo, e.g., in a mouse model. Detection of the fluorescence signals can be performed using plate readers, FACS analysis or fluorescence microscopy. In the setup described here, in vitro translocation of effector fusions into HeLa cells by different Yersinia mutants is monitored by laser scanning microscopy. Recording intracellular conversion of the FRET reporter by the beta-lactamase effector fusion in real-time provides robust quantitative results. We here show exemplary data, demonstrating increased translocation by a Y. enterocolitica YopE mutant compared to the wild type strain.

Analysis of Yersinia enterocolitica Effector Translocation into Host Cells Using Beta-lactamase Effector Fusions

Effector translocation into host cells via a type III secretion system is a common virulence strategy among gram-negative bacteria. A beta-lactamase effector fusion based assay for quantitative analysis of translocation was applied. In Yersinia infected cells, conversion of a FRET reporter by the beta-lactamase is monitored using laser scanning microscopy.

분석<em&gt; 예 르시 니아의 enterocolitica</em숙주 세포 내로&gt; 이펙터 전좌 베타 - 락타 마제 이펙터의 용해 사용

Many gram-negative bacteria including pathogenic Yersinia spp. employ type III secretion systems to translocate effector proteins into eukaryotic target ...

Measuring Phagosome pH by Ratiometric Fluorescence Microscopy

Phagocytosis is a fundamental process through which innate immune cells engulf bacteria, apoptotic cells or other foreign particles in order to kill or neutralize the ingested material, or to present it as antigens and initiate adaptive immune responses. The pH of phagosomes is a critical parameter regulating fission or fusion with endomembranes and activation of proteolytic enzymes, events that allow the phagocytic vacuole to mature into a degradative organelle. In addition, translocation of H+ is required for the production of high levels of reactive oxygen species (ROS), which are essential for efficient killing and signaling to other host tissues. Many intracellular pathogens subvert phagocytic killing by limiting phagosomal acidification, highlighting the importance of pH in phagosome biology. Here we describe a ratiometric method for measuring phagosomal pH in neutrophils using fluorescein isothiocyanate (FITC)-labeled zymosan as phagocytic targets, and live-cell imaging. The assay is based on the fluorescence properties of FITC, which is quenched by acidic pH when excited at 490 nm but not when excited at 440 nm, allowing quantification of a pH-dependent ratio, rather than absolute fluorescence, of a single dye. A detailed protocol for performing in situ dye calibration and conversion of ratio to real pH values is also provided. Single-dye ratiometric methods are generally considered superior to single wavelength or dual-dye pseudo-ratiometric protocols, as they are less sensitive to perturbations such as bleaching, focus changes, laser variations, and uneven labeling, which distort the measured signal. This method can be easily modified to measure pH in other phagocytic cell types, and zymosan can be replaced by any other amine-containing particle, from inert beads to living microorganisms. Finally, this method can be adapted to make use of other fluorescent probes sensitive to different pH ranges or other phagosomal activities, making it a generalized protocol for the functional imaging of phagosomes.

Phagosomal pH influences phagosome maturation, oxidant production, phagosomal killing as well as antigen presentation. Here we describe a ratiometric method for measuring time-course and endpoint pH changes in individual phagosomes in living phagocytes using fluorescence microscopy.

비례 형광 현미경으로 Phagosome 산도 측정

Phagocytosis is a fundamental process through which innate immune cells engulf bacteria, apoptotic cells or other foreign particles in order to kill or ...

The Development of Lyophilized Loop-mediated Isothermal Amplification Reagents for the Detection of Coxiella burnetii

Coxiella burnetii, the agent causing Q fever, is an obligate intracellular bacterium. PCR based diagnostic assays have been developed for detecting C. burnetii DNA in cell cultures and clinical samples. PCR requires specialized equipment and extensive end user training, and therefore, it is not suitable for routine work especially in a resource-constrained area. We have developed a loop-mediated isothermal amplification (LAMP) assay to detect the presence of C. burnetii in patient samples. This method is performed at a single temperature around 60 &#176;C in a water bath or heating block. The sensitivity of this LAMP assay is very similar to PCR with a detection limit of about 25 copies per reaction. This report describes the preparation of the reaction using lyophilized reagents and visualization of results using hydroxynaphthol blue (HNB) or a UV lamp with fluorescent intercalating dye in the reaction. The LAMP reagents were lyophilized and stored at room temperature (RT) for one month without loss of detection sensitivity. This LAMP assay is particularly robust because the reaction mixture preparation does not involve complex steps. This method is ideal for use in resource-limited settings where Q fever is endemic.

The Development of Lyophilized Loop-mediated Isothermal Amplification Reagents for the Detection of Coxiella burnetii

We described here a simple loop-mediated isothermal amplification (LAMP) method using lyophilized reagents for the detection of C. burnetii in patient samples.

의 탐지를위한 동결 건조 루프 - 매개 등온 증폭 시약의 개발<em&gt; Coxiella burnetii의</em

Coxiella burnetii, the agent causing Q fever, is an obligate intracellular bacterium. PCR based diagnostic assays have been developed for detecting C. ...

A Method to Assess Fc-mediated Effector Functions Induced by Influenza Hemagglutinin Specific Antibodies

Antibodies play a crucial role in coupling the innate and adaptive immune responses against viral pathogens through their antigen binding domains and Fc-regions. Here, we describe how to measure the activation of Fc effector functions by monoclonal antibodies targeting the influenza virus hemagglutinin with the use of a genetically engineered Jurkat cell line expressing an activating type 1 Fc-Fc&#947;R. Using this method, the contribution of specific Fc-Fc&#947;R interactions conferred by immunoglobulins can be determined using an in vitro assay.

We describe a method to measure the activation of Fc-mediated effector functions by antibodies that target the influenza virus hemagglutinin. This assay can also be adapted to assess the ability of monoclonal antibodies or polyclonal sera targeting other viral surface glycoproteins to induce Fc-mediated immunity.

독감 조류 특정 항 체에 의해 유도 된 Fc 중재 Effector 기능을 평가 하는 방법

Antibodies play a crucial role in coupling the innate and adaptive immune responses against viral pathogens through their antigen binding domains and ...

적용 형광 공명 에너지 전달 (FRET)을하여 이펙터 전좌 효율을 검사합니다

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