A gonococcal homologue of meningococcal γ-glutamyl transpeptidase gene is a new type of bacterial pseudogene that is transcriptionally active but phenotypically silent

Abstract

BackgroundIt has been speculated that the γ-glutamyl transpeptidase (ggt) gene is present only in Neisseria meningitidis and not among related species such as Neisseria gonorrhoeae and Neisseria lactamica, because N. meningitidis is the only bacterium with GGT activity. However, nucleotide sequences highly homologous to the meningococcal ggt gene were found in the genomes of N. gonorrhoeae isolates.ResultsThe gonococcal homologue (ggt gonococcal homologue; ggh) was analyzed. The nucleotide sequence of the ggh gene was approximately 95 % identical to that of the meningococcal ggt gene. An open reading frame in the ggh gene was disrupted by an ochre mutation and frameshift mutations induced by a 7-base deletion, but the amino acid sequences deduced from the artificially corrected ggh nucleotide sequences were approximately 97 % identical to that of the meningococcal ggt gene. The analyses of the sequences flanking the ggt and ggh genes revealed that both genes were localized in a common DNA region containing the fbp-ggt (or ggh)-glyA-opcA-dedA-abcZ gene cluster. The expression of the ggh RNA could be detected by dot blot, RT-PCR and primer extension analyses. Moreover, the truncated form of ggh-translational product was also found in some of the gonococcal isolates.ConclusionThis study has shown that the gonococcal ggh gene is a pseudogene of the meningococcal ggt gene, which can also be designated as Ψggt. The gonococcal ggh (Ψggt) gene is the first identified bacterial pseudogene that is transcriptionally active but phenotypically silent.

Structural Alterations in a Component of Cytochrome c Oxidase and Molecular Evolution of Pathogenic Neisseria in Humans

“…While PorA is a major constituent of the outer membrane of most meningococcal isolates, all strains of N. gonorrhoeae examined to date carry an identical frameshift mutation that disrupts the integrity of the porA ORF [15] . Two other genes unique to the pathogenic Neisseria , ggt and adhC (encoding gamma-glutamyl transpeptidase and S-nitrosoglutathione oxidoreductase respectively), are also intact in N. meningitidis but inactivated due to frameshift mutations in N. gonorrhoeae [16] , [17] . While the presence of these three pseudogenes in N. gonorrhoeae denotes descent from an organism carrying active forms of the genes, it remains unknown how extant isolates of N. meningitidis and N. gonorrhoeae might relate to such an ancestral population.…”

Identifying antibiotics based on structural differences in the conserved allostery from mitochondrial heme-copper oxidases

“…Neisseria gonorrhoeae mutants were constructed as described previously 78 . Briefly, in order to construct the N. gonorrhoeae norBdeficient mutant, a 4.3-kb DNA fragment from N. gonorrhoeae FA1090 chromosomal DNA containing the norB gene was amplified with the primers norB-1 and norB-2 by PrimeSTAR Max DNA polymerase (Takara Bio) and cloned into the SmaI site of the pMW119 vector (4.2 kb) (Nippon gene) to construct pHT1729 (8.5 kb).…”

The Meningococcal Cysteine Transport System Plays a Crucial Role in Neisseria meningitidis Survival in Human Brain Microvascular Endothelial Cells

“…A 3-kb DNA fragment containing the Ptac , cbp , and spc genes was amplified from pHT1386 with primers ggt-5′(15mer)-ptac-13 and ggt-3′(15mer)-ptac-14 and was inserted into a BstXI site (at the middle of the ggt coding region) of pHT624, in which the ggt gene harbored by pHT195 (81) was subcloned into pMW119, resulting in pHT1387. A 4.5-kb DNA fragment containing the ggt :: Ptac cbp spc genes was amplified with primers ggt-1 and ggt-2 (82) and transformed into the N. meningitidis cbp :: cat mutants, and spectinomycin-resistant (Spc r ) clones were selected, resulting in cbp insertional mutants ectopically complemented with the cbp gene expressed from the tac promoter at the ggt allele (Table 1).…”