The proposed research is designed to elucidate the molecular nature of the steps in the head assembly of bacteriophage P22 and the regulation of the expression of the genes involved. Emphasis is placed upon understanding the properties and biochemical mechanisms of action of the proteins involved in DNA encapsulation and cutting. Of particular interest is the product of gene 8, which acts catalytically to aid capsid assembly and acts as a type of """"""""molecular scaffold"""""""" during assembly, and whose synthesis is apparently negatively autoregulated by some feature of the assembly process. Also under study are the proteins involved in DNA packaging and cutting, gene 2 and 3 proteins. The proteins will be characterized biochemically and functionally by devising in vitro various proteins.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
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Microbial Physiology and Genetics Subcommittee 2 (MBC)
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University of Utah
Schools of Medicine
Salt Lake City
United States
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Casjens, S; Sampson, L; Randall, S et al. (1992) Molecular genetic analysis of bacteriophage P22 gene 3 product, a protein involved in the initiation of headful DNA packaging. J Mol Biol 227:1086-99
Casjens, S; Wyckoff, E; Hayden, M et al. (1992) Bacteriophage P22 portal protein is part of the gauge that regulates packing density of intravirion DNA. J Mol Biol 224:1055-74
Eppler, K; Wyckoff, E; Goates, J et al. (1991) Nucleotide sequence of the bacteriophage P22 genes required for DNA packaging. Virology 183:519-38
Casjens, S; Eppler, K; Sampson, L et al. (1991) Fine structure genetic and physical map of the gene 3 to 10 region of the bacteriophage P22 chromosome. Genetics 127:637-47
Casjens, S; Eppler, K; Parr, R et al. (1989) Nucleotide sequence of the bacteriophage P22 gene 19 to 3 region: identification of a new gene required for lysis. Virology 171:588-98
Casjens, S; Hayden, M (1988) Analysis in vivo of the bacteriophage P22 headful nuclease. J Mol Biol 199:467-74
Casjens, S; Huang, W M; Hayden, M et al. (1987) Initiation of bacteriophage P22 DNA packaging series. Analysis of a mutant that alters the DNA target specificity of the packaging apparatus. J Mol Biol 194:411-22
Wyckoff, E; Sampson, L; Hayden, M et al. (1986) Plasmid vectors useful in the study of translation initiation signals. Gene 43:281-6
Wyckoff, E; Casjens, S (1985) Autoregulation of the bacteriophage P22 scaffolding protein gene. J Virol 53:192-7
Hayden, M; Adams, M B; Casjens, S (1985) Bacteriophage L: chromosome physical map and structural proteins. Virology 147:431-40

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