Abstract

A cluster of three tRNA genes encoding a tRNA Thr UGU' a tRNA Pro UGG', and atRNA Val AAC' and two Alu-elements occur in a 6.0-kb human DNA fragment. The tRNA Thr gene is 2.7-kb upstream from the tRNA Pro gene, which is separated by 367 bp from the tRNA Val gene. One Alu-element actually overlaps the tRNA Val gene and is of opposite polarity to all three tRNA genes. All three tRNA genes are accurately transcribed in a homologous HeLa cell extract, since the ribonuclease T 1 fingerprints of the tRNA transcripts are consistent with the nucleotide sequences of the tRNAs. The upstream region flanking the tRNA Thr gene has two tracts of alternating purine/pyrimidine residues potentially capable of adopting the Z-DNA conformation, and presumptive binding sites for two RNA polymerase II transcription factors. The tRNA Thr gene apparently has a substantially higher in vitro transcriptional efficiency than the other two tRNA genes in this cluster, and a tRNA Gly GCC gene from another human DNA segment. Deletion constructs of the tRNA Thr gene retaining 272, 168, and 33 bp of original 5'-flanking DNA had about the same in vitro transcriptional efficiency, whereas that of the construct with only 2bp of 5'-flanking human DNA was drastically reduced. The tRNA Thr gene constructs with 272 and 168 bp of original 5'-flanking DNA apparently reduce the transcriptional efficiencies of the proline and glycine tRNA genes, implicating the upstream region from the tRNA Thr gene as being crucial for its high transcriptional efficiency.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.