Degree Type

Dissertation

Date of Award

1990

Degree Name

Doctor of Philosophy

Department

Genetics, Development and Cell Biology

First Advisor

John E. Mayfield

Abstract

Bovine herpesvirus-1 (BHV-1) is a member of the alphaherpesvirinae. Productive infections of the alphaherpesvirinae progress through three stages of viral transcription and translation. The first stage, immediate-early (IE), does not require prior viral gene expression and is required for the second, delayed-early (DE), and third, late (L), stages of the infectious cycle. Like other herpesviruses, BHV-1 frequently establishes latent infections. This study was undertaken to characterize the IE stage of the productive BHV-1 infection. The number and location of IE genes and the size of IE polypeptides and IE mRNAs were investigated;Probing genomic Southern blots of BHV-1 cloned in pBR322 with [superscript]32P-in vivo labeled cytoplasmic IE-RNA reveals six regions of hybridization located in HindIII clones D, J, and K. These results suggest as many as six IE genes. Sodium dodecylsulphate-polyacrylamide gel electrophoresis of [superscript]35S-methionine (met)-in vivo labeled BHV-1 polypeptides reveals at least three IE polypeptides of 180, 140, and 46 kilodaltons (kD). While [superscript]35S-methionine (met) labeled in vitro translation of poly A[superscript]+ IE-RNA reveals four polypeptides of 180, 150, 140, and 46 kD;[superscript]35S-met labeled hybrid arrested-in vitro translation of poly A[superscript]+ IE-RNA shows that two subclones of D encode three polypeptides. The polypeptide profile of hybrid arrested-in vitro translated poly A[superscript]+ IE-RNA using clones J and K to block translation were identical to unhybridized IE-RNA controls. Northern analysis of IE-RNA using pHDP4.3 as probe reveals only one transcript of 5.2 kb. These data suggest that two or three polypeptides may be translated from the same mRNA. Thus, BHV-1 (Cooper) contains at least one IE gene located within HindIII fragment D. This gene is transcribed to an mRNA of 5.2 kb. The 5.2 kb mRNA encodes two polypeptides of 180 and 140 kD, and possibly, a third of 46 kD;One in vitro translation experiment of poly A[superscript]+ IE-RNA labeled with [superscript]3H-leucine (leu) revealed seven polypeptides of 180, 150, 140, 46, 39, 37, and 35 kD. This suggests that several IE polypeptides may not contain methionine. (Abstract shortened with permission of author.)

DOI

https://doi.org/10.31274/rtd-180813-12328

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

David A. Hulce

Language

en

Proquest ID

AAI9110508

File Format

application/pdf

File Size

113 pages

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