Centro de Biotecnologia, Programa de Pós-graduação em Biologia Celular e Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
DNA Res. 2012 Apr;19(2):103-15. doi: 10.1093/dnares/dsr045. Epub 2012 Feb 14.
Several Mycoplasma species have had their genome completely sequenced, including four strains of the swine pathogen Mycoplasma hyopneumoniae. Nevertheless, little is known about the nucleotide sequences that control transcriptional initiation in these microorganisms. Therefore, with the objective of investigating the promoter sequences of M. hyopneumoniae, 23 transcriptional start sites (TSSs) of distinct genes were mapped. A pattern that resembles the σ(70) promoter -10 element was found upstream of the TSSs. However, no -35 element was distinguished. Instead, an AT-rich periodic signal was identified. About half of the experimentally defined promoters contained the motif 5'-TRTGn-3', which was identical to the -16 element usually found in Gram-positive bacteria. The defined promoters were utilized to build position-specific scoring matrices in order to scan putative promoters upstream of all coding sequences (CDSs) in the M. hyopneumoniae genome. Two hundred and one signals were found associated with 169 CDSs. Most of these sequences were located within 100 nucleotides of the start codons. This study has shown that the number of promoter-like sequences in the M. hyopneumoniae genome is more frequent than expected by chance, indicating that most of the sequences detected are probably biologically functional.
已经完成了对几种支原体物种的基因组测序，包括四种猪肺炎支原体菌株。然而，对于控制这些微生物转录起始的核苷酸序列知之甚少。因此，为了研究猪肺炎支原体的启动子序列，我们对 23 个不同基因的转录起始位点（TSS）进行了定位。在 TSS 上游发现了类似于 σ(70)启动子-10 元件的模式。然而，没有识别出-35 元件。相反，发现了一个富含 AT 的周期性信号。大约一半的实验确定的启动子包含 5'-TRTGn-3' 基序，与革兰氏阳性菌中通常发现的-16 元件相同。定义的启动子被用来构建位置特异性评分矩阵，以便在猪肺炎支原体基因组的所有编码序列（CDS）的上游扫描潜在的启动子。在 169 个 CDS 中发现了 201 个与信号相关。这些序列中的大多数位于起始密码子的 100 个核苷酸内。这项研究表明，猪肺炎支原体基因组中类似启动子序列的数量比预期的随机出现更为频繁，这表明大多数检测到的序列可能具有生物学功能。
