Effect of mutations in the cII and cIII genes of bacteriophage λ on macromolecular synthesis in infected cells

R. McMacken, N. Mantei, B. Butler, A. Joyner, H. Echols

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We have investigated the time-course of macromolecular synthesis following infection by cI-, cII- and cIII- mutants of λ in an effort to understand the role of the cII and cIII genes in the establishment of repression and lysogeny. cII- and cIII- mutants of λ begin to synthesize the "late" proteins tail antigen and lysozyme substantially before a cI- mutant; the shift to late messenger RNA production from the head and tail genes also occurs earlier after cII- or cIII- infection. In contrast, no appreciable difference among cI-, cII-, or cIII- mutants was found in synthesis of the "early" protein λ-exonuclease or in the rate of total or λ-specific DNA synthesis. These results suggest that the λ cII and cIII gene products function to delay the lytic response by inhibiting, directly or indirectly, the production of messenger RNA from the late λ genes. When lysozyme synthesis was studied after infection by cI- cII- and cI- cIII- double mutants, results were obtained which were similar to those found in the case of single cII- and cIII- mutants. The results with the double mutants suggest that the cII and cIII gene products may also participate in the regulation of cI represser synthesis or activity.

Original languageEnglish (US)
Pages (from-to)639-655
Number of pages17
JournalJournal of molecular biology
Issue number3
StatePublished - May 14 1970
Externally publishedYes


ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology

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