Retrovirus infection and aging: Increase in UAG suppressor tRNA expression in aged mice

The effect of aging on expression of a natural glutamine suppressor tRNA (tRNA(Gln(UmUG))) was studied in different tissues of mice; this tRNA recognizes UAG and inserts glutamine at the site of the termination codon. The level of tRNA(Gln(UmUG)) was found to be strongly increased in aged mice, compared to newborn and mature animals. An elevated expression of tRNA(Gln(UmUG)) has also been found in retrovirus-infected cells; in Moloney virus-infected cells the suppressor tRNA allows to read-through the UAG codon within the retroviral protease gene. We suggest that the increase in the level of tRNA(Gln(UmUG)) may influence retroviral gene expression with age.