Biomedical subjects

K Tilly

Publications and source records attributed to K Tilly.

39 records · Page 3Linked to original sources

PubMed1981

Identification of a second Escherichia coli groE gene whose product is necessary for bacteriophage morphogenesis.

Previous work has uncovered the existence of an Escherichia coli locus, groE, that is essential for bacterial growth, lambda phage and T4 phage head morphogenesis, and T5 phage tail assembly. Our genetic and biochemical analyses of lambda groE+ transducing phages and their deletion and point mutant derivatives show that the groE locus consists of two closely linked genes. One groE gene, groEL, has been shown to encode the synthesis of a 65,000 Mr polypeptide, whereas the second, groES, codes for the synthesis of a 15,000 Mr polypeptide. About half of the groE- bacterial isolates fall into the groES complementation group. GroE mutations in either gene cause similar phenotypes, with respect to lambda phage head morphogenesis and bacterial growth at nonpermissive temperatures.

Coliphages↗

PubMed1981

Studies on Escherichia coli mutants which block bacteriophage morphogenesis.

We have previously reported the isolation of E. coli groE mutants, which block lambda head morphogenesis. Further analysis of these mutants showed that many are temperature-sensitive for bacterial growth or block the growth of the unrelated phages T4 and T5. We have established the existence of a second groE gene, which we call groES, that is different from the previously described groE gene encoding a 65,000-Mr polypeptide (Georgopoulos and Hohn, 1978; Hendrix and Tsui, 1978) and which is renamed groEL. Genetic and biochemical studies of lambda groE+ transducing phages and their mutant derivatives show that these two genes are closely linked and that the groES gene codes for a polypeptide of 15,000-Mr. Bacterial groEL- or groES- mutants exhibit the same growth kinetics and phenotype at high temperature and lambda proheads have the same protein composition in both classes of mutants.

Bacterial Proteins↗

PubMed1981

Bacteriophage-host interactions in assembly.

Because of their small genome size and their parasitic way of life, bacteriophages have obligatorily evolved in such a way as to efficiently utilize many of the bacterial functions necessary for DNA replication, transcription, translation, and morphogenesis. In many instances the phage and host functions act in parallel in these processes, e.g. T4 and host DNA ligase. The specific nature of the host's contribution to phage morphogenesis is being pursued by the studies summarized here. The isolation and characterization of bacterial mutants which block phage morphogenesis, albeit at a preliminary stage, has already contributed considerable genetic information about the host's role. Future biochemical experiments, such as in vitro reconstitution, will help define the level of action of these bacterial gene products in the phage assembly process.

Bacterial Proteins↗