Evolutionary analysis of V protein pseudogenization in an RNA editing-deficient paramyxovirus

This study investigated the evolutionary consequences of RNA editing loss in human parainfluenza virus type 1 (HPIV-1) by analyzing the pseudogenization of the V protein–coding region within the P gene. The authors performed a comprehensive comparative genomic analysis using 240 full-length HPIV-1 P gene sequences and defined a pseudo-V reading frame by virtually inserting a nucleotide at the conserved RNA editing site, using Sendai virus as a reference. They observed a markedly elevated and non-random accumulation of stop codons within the 253-amino-acid pseudo-V region, with highly conserved positions across strains, indicating strong evolutionary fixation. Comparative analyses across other viral genes and with Sendai virus demonstrated that this enrichment was specific to the HPIV-1 P gene. Furthermore, in silico evolutionary simulations showed that such stop codon accumulation could not be explained solely by constraints acting on the primary open reading frame. Overall, the study demonstrates that the loss of RNA editing in HPIV-1 has driven lineage-specific pseudogenization of the V protein region, providing new insights into the evolution of overlapping gene architectures and functional gene loss in paramyxoviruses.
(TMR)