The First Human Genes for tRNAArgICG, tRNAGlyUCC, and tRNAThrIGUand More tRNAValPseudogenes: Expression and Pre-tRNA Maturation in HeLa Cell-Free Extracts

摘要

ABSTRACTA functional tRNAValgene, which codes for the major tRNAValIACisoacceptor species, and three new tRNAValpseudogenes have been isolated from human genomic DNA. Two tRNAValpseudogenes and a tRNAValvariant gene were found to be associated with tRNA genes encoding tRNAArgICG, tRNAGlyUCC, and tRNAThrIGU, respectively, on distinct DNA fragments. All tRNA genes, including the pseudogenes, are actively transcribed in HeLa nuclear extract. Pre-tRNAs of tRNAVal, tRNAArg, tRNAThr, and tRNAGlygenes are correctly processed to mature-sized tRNAs, whereas the three tRNAValpseudogenes yield stable pre-tRNAsin vitro. These findings reveal that, together with the three known pseudogenes, half of the members of the human tRNAValgene family are pseudogenes, all of which are active in homologous nuclear extractsin vitroand presumably alsoin vivo.