Head morphogenesis of bacteriophage T4 II. The role of gene 40 in initiating prehead assembly

• Published in: Virology (New York, N.Y.) Vol. 91; no. 1; pp. 15 - 25
• Main Authors: Hsiao, C.L., Black, L.W.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.11.1978
• Subjects: Capsid - biosynthesis; Coliphages - genetics; Coliphages - metabolism; Coliphages - ultrastructure; DNA, Viral - biosynthesis; Genes, Viral; Models, Biological; Morphogenesis; Recombination, Genetic; Temperature; Viral Proteins - biosynthesis; Viral Proteins - physiology
• ISSN: 0042-6822; 1096-0341
• DOI: 10.1016/0042-6822(78)90351-3

Although gene 40 function can be bypassed at low temperature, it is essential for efficient T4 head assembly. p40 appears to function at a very early stage of T4 head assembly, and this could be the reason for its location in an early gene region. p40 is not cleaved during head assembly, nor is it apparently incorporated into the mature phage particle or τ-particle. Gene 40 mutations do not affect the rate of T4-specific DNA synthesis, nor alter the regulation of RNA transcription. p40 appears to be located on the cytoplasmic membrane. Genetic evidence strongly suggests that p40 specifically interacts with p20 during an early stage of T4 prehead assembly, since secondary mutation in gene 20 can compensate for the lack of p40 at high temperature. These results are consistent with a model in which p40 helps provide a membrane-binding site for the proper assembly of p20 from which the assembly of T4 prehead on the membrane is initiated.