Identification of the putative cytadhesin gene of Mycoplasma gallisepticum and its use as a DNA probe.

A portion of the putative Mycoplasma gallisepticum (MG) cytadhesin gene was identified and used as a diagnostic DNA probe. Degenerate oligonucleotide primers corresponding to conserved regions of the cytadhesin proteins from two human mycoplasmas, M. pneumoniae and M. genitalium, were synthesized for use in the polymerase chain reaction (PCR) on genomic MG DNA. A 583-base-pair MG DNA fragment was amplified and subsequently cloned and sequenced. The MG DNA fragment is predicted to encode a 193-amino-acid peptide. This peptide demonstrates significant homology to the expected portions of the two human mycoplasmal cytadhesin proteins. Used as a probe to study the distribution of this fragment in pathogenic and nonpathogenic avian mycoplasmas, the PCR product hybridized to genomic DNA from all seven MG strains tested. However, it failed to hybridize to M. synoviae, M. meleagridis, M. iowae, or M. gallinarum DNA.