GSBS Student Publications

Title

Genetic analysis of bacteriophage P22 lysozyme structure

UMMS Affiliation

Graduate School of Biomedical Sciences; Department of Molecular Genetics and Microbiology

Date

11-1-1989

Document Type

Article

Medical Subject Headings

Base Sequence; DNA Mutational Analysis; Molecular Sequence Data; Muramidase; Mutation; Plasmids; Salmonella Phages; Suppression, Genetic

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

The suppression patterns of 11 phage P22 mutants bearing different amber mutations in the gene encoding lysozyme (19) were determined on six different amber suppressor strains. Of the 60 resulting single amino acid substitutions, 18 resulted in defects in lysozyme activity at 30 degrees; an additional seven were defective at 40 degrees. Revertants were isolated on the "missuppressing" hosts following UV mutagenesis; they were screened to distinguish primary- from second-site revertants. It was found that second-site revertants were recovered with greater efficiency if the UV-irradiated phage stocks were passaged through an intermediate host in liquid culture rather than plated directly on the nonpermissive host. Eleven second-site revertants (isolated as suppressors of five deleterious substitutions) were sequenced: four were intragenic, five extragenic; three of the extragenic revertants were found to have alterations near and upstream from gene 19, in gene 13. Lysozyme genes from the intragenic revertant phages were introduced into unmutagenized P22, and found to confer the revertant plating phenotype.

Rights and Permissions

Citation: Genetics. 1989 Nov;123(3):431-40.

Related Resources

Link to Article in PubMed

Journal Title

Genetics

PubMed ID

2599364