Accession Number : ADA182327

Title :   Lambda N Antitermination System: Functional Analysis of Phage Interactions with the Host NusA Protein,

Corporate Author : WALTER REED ARMY INST OF RESEARCH WASHINGTON DC

Personal Author(s) : Schauer,Alan T. ; Carver,Debra L. ; Bigelow,Bradley ; Baron,L. S. ; Friedman,David I.

Report Date : 1987

Pagination or Media Count : 14

Abstract : Coliphage ambda gene expression is regulated temporally by systems of termination and antitermination of transcription. The lambda-encoded N protein (pN) acting with host factors (Nus) at sites (nut) located downstream from early promoters is the first of these systems to operate during phage development. We report observations on some of the components of this complex system that, in part, address the way in which these elements interact to render RNA polymerase termination-resistant. (1) The isolation of a conditionally lethal cold-sensitive nusA mutation demonstrates that NusA is essential for bacterial growth. (2) The effect on lambda growth in a host in which the Salmonella NusA protein is overproduced suggests that NusA is essential for N-mediated antitermination in phage lambda (3) A truncated NusA product, representing only the amino two-thirds of the native protein, is active for both bacterial growth and pN action, indicating that the carboxy end of the molecule may not be a functionally important region (4) lambdapN can function with the heterologous nut region from Salmonella typhimurium phage P22 when lambda pN is overproduced, demonstrating that lambda pN can function with the nut regions of other lambdoid phages. (5) A single base-pair change in the lambda nutR boxA sequence that was selected to permit a lambda derivative to utilize the Salmonella NusA protein restores lambda growth in the Escherichia colinusA1 host. (Reprints).

Descriptors :   *PROTEINS, *COLIPHAGE, *GENES, *HOSTS(BIOLOGY), RESISTANCE(BIOLOGY), SITES, STOPPING, ESCHERICHIA COLI, mUTATIONS, IMMUNOLOGY, BACTERIA, BACTERIOPHAGES, FUNCTIONAL ANALYSIS, GROWTH(PHYSIOLOGY), INTERACTIONS, ISOLATION, REPRINTS, SALMONELLA

Subject Categories : Microbiology
      Genetic Engineering and Molecular Biology
      Biochemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE