Analysis of cis Elements in the mp50 mRNA of Trichomonas vaginalis

Trichomonas vaginalis is the protozoan parasite responsible for trichomoniasis, a prevalent non-viral sexually transmitted disease where high Zn2+ concentrations in the male prostate microenvironment function as a natural infection barrier. This study evaluates the post-transcriptional mechanisms governing the gene expression and mRNA stability of the 50 kDa metalloproteinase (TvMP50), an immunogenic biomarker for male trichomoniasis, under zinc stress. Using T. vaginalis female (CNCD147) and male (HGMN01) isolates, mp50 expression was characterized through transcription inhibition assays with Actinomycin-D, 5′ RACE, 3′ RACE, poly (A) tail assays (PAT-PCR), and Mfold secondary structure modeling. Results demonstrated that while transcription consistently initiates at a 10-nucleotide sequence relative to the start codon, the presence of 1.6 mM Zn2+ significantly stabilizes the transcript, extending its experimental half-life from 30 to 47 min. Furthermore, PAT-PCR and sequencing confirmed that Zn2+ exposure alters poly (A) tract lengths, reaching up to ~700 nucleotides, and utilizes alternative polyadenylation and cleavage sites to form stable 3′ untranslated region stem-loop configurations. In conclusion, mp50 overexpression under zinc stress is driven by a post-transcriptional mechanism where the synergistic effect of alternative processing signals and longer poly (A) tails enhances mRNA stability, optimizing parasite virulence during male urogenital colonization.