ISSN:
1617-4623
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary The fate of the λ repressor on induction of E. coli lysogens has been studied after γ-irradiation, mitomycin C treatment or by temperature step-up of a tif-1 mutant. The repressor and a fragment of the repressor were selectively precipitated from labelled cell lysates by anti-repressor serum and subjected to gel electrophoresis and autoradiography. Induction of lysogens by all of these treatments leads to cleavage of the repressor. Repressor cleavage closely parallels the inactivation of its DNA binding properties and seems to be the general fate of the repressor on induction, irrespective of the nature of the inducing treatment. The effect of chloramphenicol on the cleavage has been studied in order to assess the requirement for inducible protein synthesis in this process. In contrast to results obtained by mitomycin C treatment, tif mediated cleavage of the repressor does not require the induction of new protein synthesis. Although inactivation of the DNA binding properties of the repressor after induction by λ-irradiation does not appear to be inhibited by chloramphenicol (West, Powell and Emmerson, 1975), cleavage of the repressor is substantially inhibited by this compound. The possible implications of these findings are discussed in relation to inducible repair functions and the mechanism of repressor inactivation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00268564
