P2 phage amber mutants: Characterization by use of a polarity supressor

Bacteriophage P2

“…Tail genes VWJIHG are expressed in a single transcription unit. [50][51][52] In phage 186, however, these genes are cotranscribed with the upstream capsid-lysis-tail gene operon. 53 The product of gene V makes up the small spike at the tip of the tail; it is a trimeric iron-binding protein involved in membrane penetration.…”

“…59 The tail genes F I , F II , E, T, U and D comprise a single transcription unit. 50,52 Gene F I encodes the tail sheath, and F II encodes the tail tube. 60 Gene E contains a programmed translational frameshift, allowing it to make a shorter (E) and a longer (ECE') protein, both of which are essential for phage growth.…”

A Transcribing Activity Induced by Satellite Phage P4

“…For * The effect of P4 A gene amber mutants on enzyme synthesis is probably not due to a polar effect, since similar results are obtained in a host strain carrying a polarity suppressor (26). E. coli C-1748 was grown in A medium to-a density of 5 X 108 cells per ml.…”

“…P2 and P4 phage preparations, which had been banded twice in CsCl density gradients, were used for isolation of DNA (15). The integrity of phage DNA was measured by alkaline zonal sedimentation in an analytical ultracentrifuge (16 26 and P4 vir, tsBrn are described by Gibbs et al (13).…”

Determination of capsid size by satellite bacteriophage P4.

“…The ig mutation corrects for a defect in particle assembly, thereby allowing for a larger burst size (11). Derivatives of strain C-la containing the supD and supF amber suppressors are described by Sunshine et al (12). The streptomycin-resistant strain C-1758 is described by Gibbs et al (8).…”