Genome Analysis of a Mycoplasma hyorhinis Strain Derived from a Primary Human Melanoma Cell Line

Abstract

The complete genome of Mycoplasma hyorhinis strain MCLD has been sequenced and annotated. This genome differs by the inversion of a 14.4-kb and a 3.7-kb fragment and the deletion of a 9.9-kb fragment from M. hyorhinis strain HUB-1, isolated from swine respiratory tract. The genome revealed 778 coding sequences (CDSs), with a limited number of vlp genes encoding variable surface lipoproteins.Mycoplasma hyorhinis is a swine pathogen causing respiratory diseases and arthritis. Additionally, it is a frequent cell culture contaminant and has recently been detected in human gastric carcinoma tissues (13). M. hyorhinis MCLD has been isolated from a primary human melanoma cell line (5). Although mycoplasmas were considered adherent extracellular microorganisms (10), it has been shown that M. hyorhinis MCLD invades host cells (7). Furthermore, host cells infected with M. hyorhinis MCLD showed elevated expression of a CD99 ligand on melanoma cells (5) and a marked increase in the cellular concentration of the protease inhibitor calpastatin within infected neuroblastoma cells (4).The M. hyorhinis MCLD genome was sequenced by using GS FLX Titanium technology and annotated using RAST (1) and PGAAP with manual curation. The fully assembled circular chromosome has 829,709 bp and an average GϩC content of 25.9%. We predicted 778 coding sequences (CDSs) with a coding density of 89.2%, of which 273 CDSs were hypothetical or conserved hypothetical proteins.Genome alignment of M. hyorhinis MCLD with the M. hyorhinis HUB-1 sequence (8), starting at the dnaA gene (SRH_2175) in the reverse complement orientation and using MAUVE (3), revealed 18 locally colinear blocks (LCBs). Unlike recent data on M. mycoides (12), no function-specific LCBs were identified. The MAUVE progressive mode utilized to identify conserved large segments revealed that each chromosome was composed of 4 regions and that differences may be explained by 2 inversions (14.4 kb, SRH_02645 to SRH_02545, and 3.7 kb, SRH_2605 to SRH_2635).Similar to other mycoplasmas, 10 putative transcriptional regulators were detected in the M. hyorhinis MCLD genome, among them two sigma factors and the transcriptional repressor HrcA. Unlike other mycoplasma species, no homologs of the RelA and SpoT families were found.The bacterial translational system components are conserved and included 30 tRNAs and 21 tRNA synthetases, a single copy of the 16S-23S rRNA operon, and a separate 5S rRNA gene. Three protein initiation factors, 4 elongation factors, and a single peptide release factor (RF-1) were also identified. However, the peptide chain release factor 2 (RF-2) was not detected.It has been proposed that the variable surface lipoprotein (vlp) locus in M. hyorhinis contains seven distinct vlp genes (2). Comparative analysis of the vlp locus among five M. hyorhinis strains (MCLD, GDL, SK76, HUB-1, and a clonal variant of SK76) revealed that the vlp genes in M. hyorhinis MCLD are reduced, containing only 4 genes, vlpD (SRH_00185), vlpE (SRH_00180), vlpB (SRH_00175), and vlpC (SRH_00170),...

Mycoplasma Hyorhinis Infection Promotes NF-κB–Dependent Migration of Gastric Cancer Cells

“…There would be a quick decline in the success of PCR for large fragment after storage in FFPE after 1 to 2 years (33). Moreover, formalin can introduce damages to AT-rich regions of DNA (34), whereas M. hyorhinis genome has an A-T content of more than 74% (35). For these reasons, it is hard to validate the IHC results by qPCR for samples of cohort 1, which were collected 10 to 16 years ago.…”

Multilocus Sequence Typing of Mycoplasma hyorhinis Strains Identified by a Real-Time TaqMan PCR Assay

“…Six housekeeping genes were chosen for MLST based on the sequenced genomes of M. hyorhinis strains HUB-1, GDL-1, MCLD, and SK76 (31,(35)(36)(37). Internal fragments of the chromosomal replication initiation protein (dnaA), RNA polymerase ␤ subunit (rpoB), DNA gyrase subunit B (gyrB), glutamyl-tRNA synthetase (gltX), adenylate kinase (adk), and guanylate kinase (gmk) genes were selected.…”

Complete Genome Sequence of Mycoplasma hyorhinis Strain SK76

“…Here, we report the complete genome sequence of M. hyorhinis strain SK76 (clonal isolate 8II), an arthritogenic strain that was derived from a naturally infected disease site (7–9). While this study was in progress, the genome sequences of three other M. hyorhinis strains were reported (10–12). …”