The 5$ sp prime$ untranslated region (UTR) of c-myc and human immunodeficiency virus type 1 (HIV-1) mRNAs were used as models in a variety of in vitro and in vivo systems in order to study the role of this region in the control of eukaryotic gene expression. Using an ultraviolet light-induced crosslinking assay, a 55 kilodalton protein was identified in extracts of HeLa, mouse erythroleukemia, and other cell lines, which interacts specifically with a purine-rich RNA sequence in the 5$ sp prime$ UTR of c-myc. The function of this protein in control of c-myc expression is not known, but may be implicated in the process of transcriptional elongation. The 5$ sp prime$ UTR of HIV-1 mRNAs was shown to inhibit strongly the translation of a heterologous mRNA; this inhibition was dependent on the secondary structure predicted to form in this region, and on the accessibility of the cap structure to initiation factors. The structural requirements in the HIV-1 5$ sp prime$ UTR for trans-activation by the viral tat gene product were examined by mutagenesis studies; the base-pairing in the stem-loop structure, the sequence of the loop, and the presence of a three nucleotide bulge were found to be critical features necessary for complete trans-activation. These findings indicate that the 5$ sp prime$ UTR can have important effects on the expression of eukaryotic genes.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.74327 |
| Date | January 1989 |
| Creators | Parkin, Neil T. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Biochemistry.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001069299, proquestno: AAINN63652, Theses scanned by UMI/ProQuest. |
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