Deng Y M, Liu C Q, Dunn N W
Department of Biotechnology, University of New South Wales, Sydney, Australia.
J Biotechnol. 1999 Jan 22;67(2-3):135-49. doi: 10.1016/s0168-1656(98)00175-8.
A plasmid-encoded phage abortive infection mechanism (AbiL) was identified from Lactococcus lactis biovar. diacetylactis LD10-1. AbiL conferred complete resistance to the small isometric-headed phage phi 712 (936 species) and partial resistance to the prolate-headed phage phi c2 (c2 species) when introduced into L. lactis LM0230. However, AbiL was not effective against the small isometric-headed phage ul36 (P335 species). The AbiL determinant was sequenced and it consists of two open reading frames, abiLi and abiLii. Their encoded proteins did not share significant homology with any known proteins in the protein databases. Transcriptional analysis indicated that abiLi and abiLii are organized as a single operon. Deletion within abiLii abolished the phage resistance. The levels of four phi c2-specific transcripts, three within the early transcribed region and one within the late transcribed region, were examined by RT-PCR, no effect of AbiL on synthesis of these transcripts was detected, suggesting that AbiL may act at a point after the transcription of phi c2 in L. lactis.
从乳酸乳球菌双乙酰亚种LD10-1中鉴定出一种质粒编码的噬菌体流产感染机制（AbiL）。当将AbiL导入乳酸乳球菌LM0230时，它赋予了对小等轴头噬菌体phi 712（936种）的完全抗性以及对长头噬菌体phi c2（c2种）的部分抗性。然而，AbiL对小等轴头噬菌体ul36（P335种）无效。对AbiL决定簇进行了测序，它由两个开放阅读框abiLi和abiLii组成。它们编码的蛋白质与蛋白质数据库中的任何已知蛋白质均无显著同源性。转录分析表明，abiLi和abiLii组成一个单一操纵子。abiLii内的缺失消除了噬菌体抗性。通过逆转录聚合酶链反应检测了四种phi c2特异性转录本的水平，其中三种在早期转录区域，一种在晚期转录区域，未检测到AbiL对这些转录本合成的影响，这表明AbiL可能在乳酸乳球菌中phi c2转录后的某个点起作用。
