Date of Award

5-1-1985

Degree Type

Dissertation

University or Center

Atlanta University (AU)

Degree Name

Ph.D.

Department

Biology

First Advisor

Dr. Joe Johnson

Abstract

All eukaryotic mRNAs analyzed to date contain, at their 5' end, a cap structure consisting of a reversed 7-methyl guanosine residue linked at the 5' position of the ribose by a triphosphate to the 5'- position of the terminal residue. Since its discovery, the cap structure has been shown to play an important role in the control of initiation of protein synthesis. Further characterization of mRNAs has revealed other unique properties. Its 3' terminus in most eukaryotes is enriched with a sequence of adenylic acid residues called the poly(A) tail. Photoaffinity binding studies, using photoaffinity capped mRNAs and mRNAs polyadenylated with a photoaffinity label translated in a rabbit reticulocyte lysate system, suggest that proteins or initiation factors are associated with both the 5' and 3' ends. The ability for ribosomes to form complexes in a rabbit reticulocyte lysate system was tested by modi fying mRNAs using 8-azido-[32P]GTP and 8-azido-[32P]ATP. The extent of binding was measured by the total amount of photoaffinity label recovered from a 12% SDS-polyacrylamide gel cut into 1 mm stripes and counted in a LS 7000 scintillation counter. Several proteins labeled both at the 5' and 3' ends with the photoaffinity probe appear to be ribonuclear proteins.

Included in

Biology Commons

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