Bintrim S B, Ensign J C
Department of Bacteriology, The University of Wisconsin-Madison, 53706, USA.
J Bacteriol. 1998 Mar;180(5):1261-9. doi: 10.1128/JB.180.5.1261-1269.1998.
The entomopathogenic bacterium Photorhabdus luminescens exhibits phase variation when cultured in vitro. The variant forms of P. luminescens are pleiotropic and are designated phase I and phase II variants. One of the characteristic phenotypes of phase I cells is the production of two types of intracellular protein inclusions. The genes encoding the protein monomers that form these inclusions, designated cipA and cipB, were cloned and characterized. cipA and cipB encode hydrophobic proteins of 11,648 and 11,308 Da, respectively. The deduced amino acid sequences of CipA and CipB have no significant amino acid sequence similarity to any other known protein but have 25% identity and 49% similarity to each other. Insertional inactivation of cipA or cipB in phase I cells of P. luminescens produced mutants that differ from phase I cells in bioluminescence, the pattern and activities of extracellular products, biochemical traits, adsorption of dyes, and ability to support nematode growth and reproduction. In general, the cip mutants were phenotypically more similar to each other than to either phase I or phase II variants.
昆虫病原细菌发光光杆状菌在体外培养时会表现出相变。发光光杆状菌的变体形式具有多效性，被指定为I相和II相变体。I相细胞的特征表型之一是产生两种类型的细胞内蛋白质内含物。编码形成这些内含物的蛋白质单体的基因，分别命名为cipA和cipB，被克隆并进行了表征。cipA和cipB分别编码11,648 Da和11,308 Da的疏水蛋白。CipA和CipB的推导氨基酸序列与任何其他已知蛋白质没有明显的氨基酸序列相似性，但彼此之间有25%的同一性和49%的相似性。在发光光杆状菌的I相细胞中cipA或cipB的插入失活产生了突变体，这些突变体在生物发光、细胞外产物的模式和活性、生化特性、染料吸附以及支持线虫生长和繁殖的能力方面与I相细胞不同。一般来说，cip突变体在表型上彼此之间比与I相或II相变体更相似。
