Regulation of bovine papillomavirus DNA replication by phosphorylation of the viral E1 protein /
While much is known about the basic enzymology and mechanisms of DNA replication, much less is known about the proteins and mechanisms involved in the regulation of DNA replication. El is the replication initiator protein for bovine papillomavirus (BPV) and carries out enzymatic functions required...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1997.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=736584741&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | While much is known about the basic enzymology and mechanisms of DNA replication, much less is known about the proteins and mechanisms involved in the regulation of DNA replication. El is the replication initiator protein for bovine papillomavirus (BPV) and carries out enzymatic functions required for initiation of viral DNA replication. BPV DNA replication is likely to be regulated by the same mechanisms that regulate cellular DNA replication. The experiments described in this dissertation were designed to investigate the role of phosphorylation in regulating the replication functions of the El protein of BPV. Serine 109 of El is a phosphoacceptor in vivo and is phosphorylated in vitro by protein kinase A and protein kinase C. A viral genome carrying a serine 109 to alanine mutation replicates more efficiently than wild-type in phenotype appears to be due to an increase in origin DNA vivo. This replication binding activity of the mutant El protein. In contrast, a viral genome carrying a serine 584 to alanine (S584A) mutation in El fails to replicate in vivo. Serine 584 is phosphorylated in vitro by casein kinase I and casein kinase 11. Purified El S584A mutant protein has wild-type ATPase and DNA helicase activities and has significant origin DNA binding activity. The molecular basis for the replication phenotype of the El S584A mutant remains unknown. Serine 90 of El is also phosphorylated in vitro by protein kinase A and protein kinase C. A serine 90 to alanine (S90A) mutation also causes an increase in viral DNA replication in vivo. However, there is not an increase in origin DNA binding as seen with the S109A mutant. Instead, the S90A mutant El protein appears to have an increased DNA helicase activity compared to wild-type. These results provide evidence that the BPV El protein is both positively and negatively regulated by phosphorylation. These results are similar to those found with SV40 large T antigen, another replication initiator protein. It is likely that phosphorylation will also play a role in regulating the initiation of cellular DNA replication. |
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| Item Description: | Vita. "Major Subject: Biochemistry". In title, numerals are used. |
| Physical Description: | xi, 140 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 114-124. |