Functional characterization of the Autographa californica nuclear polyhedrosis virus 25K gene product /
culture results in the appearance of viruses exhibiting the "few polyhedra' (FP) phenotype. A large proportion of FP viruses bear mutations in the 25K gene. Studies were conducted to determine the role of the Autographa califomica nuclear polyhedrosis virus 25K gene in the occurrence of...
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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=739363781&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | culture results in the appearance of viruses exhibiting the "few polyhedra' (FP) phenotype. A large proportion of FP viruses bear mutations in the 25K gene. Studies were conducted to determine the role of the Autographa califomica nuclear polyhedrosis virus 25K gene in the occurrence of the FP phenotype and in occluded virus assembly. Characterization of AcMNPV 25K mutants indicated that mutations in the 25K gene accounted for the failure of FP viruses to occlude virions and to envelop nucleocapsids in the nucleus. 25K mutants also produced increased quantities of budded virus. Polyclonal antibodies recognizing the 25K protein were generated and used to characterize 25K biosynthesis and localization. The 25K protein accumulated in cytosolic and nuclear fractions during the late phase of infection. It was shown not to be a major structural component of the virion, nor was it directly associated with occluded virus assembly events in the nucleus. Instead, the 25K protein was associated predominantly with amorphous masses in the cytoplasm. A minor quantity of 25K was also present in the nucleus in association with a more electron dense structure. A previous study revealed that polyhedrin protein synthesis was reduced in cells infected with a 25K mutant. Further studies were carried out to define the role of the 25K gene in viral gene expression. Expression of the polyhedrin (polh) gene was found to be reduced at the level of transcription in 25K mutant-infected cells. Expression of p10, the other baculovirus very late. gene, was not reduced. Although two-dimensional gel electrophoresis of protein samples did not reveal an extensive effect on viral gene expression, western blot analysis with antisera recognizing occlusion-derived virus proteins showed alterations in the quantities of viral proteins which correlated with 25K mutation. Although levels of the ODV-E66 envelope protein were reduced in 25K mutant protein samples, the RNA levels of the gene encoding this protein were not reduced. Overall, these results suggest that the 25K protein participates indirectly in occluded virus assembly by controlling expression of genes required for the assembly process. |
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| Item Description: | Vita. "Major Subject: Biochemistry". In title, numerals are used. |
| Physical Description: | x, 172 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 142-166. |