Markham Philip F, Duffy Michael F, Glew Michelle D, Browning Glenn F
Microbiology (Reading). 1999 Aug;145 ( Pt 8):2095-2103. doi: 10.1099/13500872-145-8-2095.
The avian pathogen Mycoplasma gallisepticum possesses a large gene family encoding lipoproteins which function as haemagglutinins. Representative species of the pneumoniae phylogenetic group of mycoplasmas were examined for the presence of genes homologous to members of this multigene family. Antisera against the pMGA1.1 lipoprotein recognized a 35 kDa protein in Mycoplasma imitans, but did not recognize proteins of Mycoplasma genitalium, Mycoplasma pneumoniae, Mycoplasma pirum, Mycoplasma penetrans of Mycoplasma iowae in Western blots. A fragment of the pMGA 1.2 gene and oligonucleotide probes complementary to highly conserved coding and non-coding regions of pMGA genes bound to fragments of genomic DNA of M. imitans, but not to the genomes of M. genitalium, M. pneumoniae, M. pirum or M. penetrans, and only one probe bound to a fragment of the M. iowae genome. One homologue of the pMGA genes was amplified from the M. imitans genome by PCR and used as a probe to clone a 3.1 kbp DNA fragment from a library of HindIII-digested M. imitans genomic DNA. The contiguous DNA sequence of the PCR and HindIII clones was predicted to encode one complete and one partial ORF which shared some peptide sequence identity with the pMGA genes, including the signal peptidase II cleavage site and the proline-rich amino-terminal region. Like the pMGA genes, the M. imitans genes were found to be members of a large gene family, with an association with GAA trinucleotide repeats, a feature which distinguishes these two families from the homologous vlhA gene family in Mycoplasma synoviae. The identification of these gene families in three phylogenetically distinct avian mycoplasma species, but not in human mycoplasmas, suggests their horizontal transfer between species infecting the same host.
禽病原体鸡毒支原体拥有一个编码脂蛋白的大基因家族，这些脂蛋白发挥血凝素的功能。对支原体肺炎系统发育组的代表性物种进行检测，以确定是否存在与这个多基因家族成员同源的基因。抗pMGA1.1脂蛋白的抗血清在模仿支原体中识别出一种35 kDa的蛋白质，但在蛋白质免疫印迹中未识别出生殖支原体、肺炎支原体、梨支原体、穿透支原体或伊氏支原体的蛋白质。pMGA 1.2基因的一个片段以及与pMGA基因高度保守的编码区和非编码区互补的寡核苷酸探针与模仿支原体的基因组DNA片段结合，但不与生殖支原体、肺炎支原体、梨支原体或穿透支原体的基因组结合，并且只有一个探针与伊氏支原体基因组的一个片段结合。通过PCR从模仿支原体基因组中扩增出一个pMGA基因的同源物，并将其用作探针，从经HindIII消化的模仿支原体基因组DNA文库中克隆出一个3.1 kbp的DNA片段。预测PCR克隆和HindIII克隆的连续DNA序列编码一个完整的开放阅读框（ORF）和一个部分ORF，它们与pMGA基因共享一些肽序列同一性，包括信号肽酶II切割位点和富含脯氨酸的氨基末端区域。与pMGA基因一样，发现模仿支原体基因是一个大基因家族的成员，与GAA三核苷酸重复序列相关，这一特征将这两个家族与滑膜支原体中的同源vlhA基因家族区分开来。在三种系统发育上不同的禽支原体物种中鉴定出这些基因家族，而在人支原体中未鉴定出，这表明它们在感染同一宿主的物种之间进行了水平转移。
