An accessory protein to DNA polymerase Alpha exhibits structural and functional similarities to SV40 large T antigen /
Investigators have suggested the probable existence of a a normal cellular homolog to SV40 large T antigen (TAg). This putative homolog is proposed to be an ATP-dependent helicase,bind to origin DNA sequences, interact directly with the DNA polymerase a/primase (pol a/primase) complex, be stimulato...
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| Format: | Thesis Book |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
1996.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=743273461&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Investigators have suggested the probable existence of a a normal cellular homolog to SV40 large T antigen (TAg). This putative homolog is proposed to be an ATP-dependent helicase,bind to origin DNA sequences, interact directly with the DNA polymerase a/primase (pol a/primase) complex, be stimulatory to pol a/primase, interact in Go and early G, with the normal cellular homolog to SV40 large T antigen (TAg). This putative homolog is proposed to be an ATP-dependent helicase, bind to origin DNA sequences, interact directly with the DNA polymerase a/primase (pol a/primase) complex, be stimulatory to pol a/primase, interact in Go and early G, with the retinoblastoma protein (Rb), and be regulated by phosphorylation. This cellular protein should also contain amino acid sequences similar to those of TAg at Rb and pol a binding sites. A comparison between TAg and a putative homolog, a accessory protein (aAP), was completed with individually purified proteins. TAg and Rb were purified, in an active form, from recombinant baculovirus-infected Spodopteraftugiperda (SJ9) cells. Pol a/primase and aAP were purified from a mouse leukemia cell line, L 12 1 0. TAg copurified with SJ9 DNA pol a, allowing a comparison of pol a binding characteristics between TAg and aAP. TAg also interacted with purified Rb protein. Coimmunoprecipitation of TAg and Rb, or aAP and Rb, and pol a activity assays were completed to determine the nature of the interaction between aAP and Rb and to investigate the functional consequences of this interaction. Western immunoanalysis was used to determine whether aAP shared epitope similarities with TAg. TAg and aAP were immunoreactive with anti-TAg monoclonal antibodies. TAg and aAP were reciprocally coimmunoprecipitated with Rb protein. Both proteins demonstrated altered function upon interaction with Rb protein, showing an inhibition of their pol a stimulatory capabilities. Lastly, both proteins interacted and copurified with pol a isolated by column chromatography. Given these and other functional similarities between TAg and aAP, aAP is a candidate cellular homolog for TAg. |
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| Item Description: | Vita. "Major Subject: Genetics". In title, numerals and symbols are used. Alpha appears as symbol on piece. |
| Physical Description: | ix, 112 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references. |