The spore-forming, anaerobic Gram positive pathogen Clostridium perfringens encodes many of its disease-causing toxins on closely related conjugative plasmids. Studies of the tetracycline resistance plasmid pCW3 have identified many of the genes involved in conjugative transfer, which are located in the tcp conjugation locus. Upstream of this locus is an uncharacterised region (the cnaC region) that is highly conserved. This study examined the importance in pCW3 conjugation of several highly conserved proteins encoded in the cnaC region. Conjugative mating studies suggested that the SrtD, TcpN and Dam proteins were required for efficient pCW3 transfer between C. perfringens cells from the same strain background. The requirement of these proteins for conjugation was amplified in matings between C. perfringens cells of different strain backgrounds. Additionally, the putative collagen adhesin protein, CnaC, was only required for the optimal transfer of pCW3 between cells of different strain backgrounds. Based on these studies we postulate that CnaC, SrtD, TcpN and Dam are involved in enhancing the transfer frequency of pCW3. These studies have led to a significant expansion of the tcp conjugation locus, which now encompasses a 19 kb region.

形成孢子的厌氧革兰氏阳性病原体产气荚膜梭菌在密切相关的接合质粒上编码其许多致病毒素。对四环素抗性质粒 pCW3 的研究已经鉴定了许多参与接合转移的基因，这些基因位于tcp接合位点。该基因座的上游是高度保守的未表征区域（cnaC区域）。该研究检查了在cnaC区域编码的几种高度保守的蛋白质在 pCW3 缀合中的重要性。共轭交配研究表明 SrtD、TcpN 和 Dam 蛋白是产气荚膜梭菌之间有效 pCW3 转移所必需的来自同一菌株背景的细胞。在不同菌株背景的产气荚膜梭菌细胞之间的交配中，这些蛋白质对缀合的需求被放大。此外，推定的胶原粘附蛋白 CnaC 只需要在不同菌株背景的细胞之间实现 pCW3 的最佳转移。基于这些研究，我们假设 CnaC、SrtD、TcpN 和 Dam 参与提高 pCW3 的转移频率。这些研究导致tcp共轭位点的显着扩展，其现在包含 19 kb 区域。