Liu Guannan, She Qunxin, Garrett Roger A
Archaea Centre, Department of Biology, University of Copenhagen, DK-2200 Copenhagen N, Denmark.
Archaea Centre, Department of Biology, University of Copenhagen, DK-2200 Copenhagen N, Denmark
Nucleic Acids Res. 2016 May 19;44(9):4233-42. doi: 10.1093/nar/gkw286. Epub 2016 Apr 20.
The Sulfolobales host a unique family of crenarchaeal conjugative plasmids some of which undergo complex rearrangements intracellularly. Here we examined the conjugation cycle of pKEF9 in the recipient strain Sulfolobus islandicus REY15A. The plasmid conjugated and replicated rapidly generating high average copy numbers which led to strong growth retardation that was coincident with activation of CRISPR-Cas adaptation. Simultaneously, intracellular DNA was extensively degraded and this also occurred in a conjugated Δcas6 mutant lacking a CRISPR-Cas immune response. Furthermore, the integrated forms of pKEF9 in the donor Sulfolobus solfataricus P1 and recipient host were specifically corrupted by transposable orfB elements, indicative of a dual mechanism for inactivating free and integrated forms of the plasmid. In addition, the CRISPR locus of pKEF9 was progressively deleted when conjugated into the recipient strain. Factors influencing activation of CRISPR-Cas adaptation in the recipient strain are considered, including the first evidence for a possible priming effect in Sulfolobus The 3-Mbp genome sequence of the donor P1 strain is presented.
硫化叶菌目拥有一个独特的泉古菌接合质粒家族，其中一些质粒在细胞内会发生复杂的重排。在此，我们研究了pKEF9在受体菌株冰岛硫化叶菌REY15A中的接合循环。该质粒快速接合并复制，产生高平均拷贝数，导致强烈的生长迟缓，这与CRISPR-Cas适应性激活同时发生。同时，细胞内DNA被广泛降解，在缺乏CRISPR-Cas免疫反应的接合Δcas6突变体中也出现这种情况。此外，供体嗜热栖热菌P1和受体宿主中pKEF9的整合形式被转座orfB元件特异性破坏，这表明存在使质粒游离形式和整合形式失活的双重机制。此外，pKEF9的CRISPR位点在接合到受体菌株中时会逐渐缺失。我们考虑了影响受体菌株中CRISPR-Cas适应性激活的因素，包括在硫化叶菌中可能存在引发效应的首个证据。还给出了供体P1菌株的3-Mbp基因组序列。
