Date of Award

Summer 1988

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biological Sciences

Program/Concentration

Biomedical Sciences

Committee Director

Alva H. Johnson

Committee Member

Neal Young

Committee Member

James H. Yuan

Committee Member

Mark Elliott

Abstract

The B19 (human) parvovirus is a small single stranded DNA virus of 5.4 kilobases. B19 is specific for erythroid progenitor cells and has been propagated in vitro only with human erythroid bone marrow. Replication of viral DNA and the viral protein products of B19 appear similar to those of other animal parvoviruses. However, B19 differs from other parvoviruses in some important aspects, which include the initiation of all transcripts at a strong left side promoter (p6) and the absence of a functional internal promoter. B19 has an unusual transcription map which is described in this study.

The transcription map of B19 suggested overlapping transcripts with the same initiation and termination sites and containing introns of differing sizes. Model experiments were performed to test the validity of two dimensional exonuclease VII analysis of overlapping transcripts. The transcripts were hybridized with a DNA probe and digested with exonuclease VII. Single bands were resolved into components of appropriate sizes by two dimensional electrophoresis.

The overlapping transcripts of B19 produce two capsid proteins, namely VP1 and VP2, where VP1 is the major protein produced. Immediately upstream from the VP1 translation site is an unusual sequence containing multiple ATG codons. During processing, this sequence is spliced out of VP2 RNA. A set of experiments were performed using synthetic RNAs to determine the role of these upstream spurious AUGs on translation. Translation of VP1 RNA was very inefficient compared to VP2 RNA in a cell free system, indicating that capsid protein production was regulated at the level of translation.

DOI

10.25777/f2r0-d006

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