Gene N and Membrane Association of Lambda DNA

Abstract

The expression of the early and late genes of λ is regulated by the N gene function (Dove, 1968; Echols and Joyner, 1968). Regulator gene N has a pleiotrophic effect on RNA transcription (Skalka et al., 1967; Taylor et al., 1967; Cohen and Hurwitz, 1968) and DNA replication (Eisen et al., 1966; Joyner et al., 1966; Ogawa and Tomizawa, 1968). Hallick et al. (1969) have presented evidence that N gene function is required for the association of λ DNA with membrane (a cellular structure which sedimented very rapidly after gentle lysis) and proposed that gene N may carry out its regulation of RNA transcription and DNA replication through direct control of membrane association. Replication and membrane association of the DNA of λ operator-and promoter-mutants, virCR, virL (Horiuchi et al., 1969), c17 (Pereira da Silva and Jacob, 1968), and ri^c5b (Dove et al., 1969), were studied in the presence of represser. The results show that the λ gene product participates indirectly rather than directly in DNA-membrane association through its regulation of transcription.

INDIRECT ROLE OF N GENE FUNCTION ON MEMBRANE ASSOCIATION
Operator mutants virCR and virL express the operons on the right and left sides of the immunity region in the presence of represser (Eshima et al., in preparation), as v1v3 and v2 do (Ptashne and Hopkins, 1968). virCR but not virL shows constitutive DNA replication in λ lysogens, as shown in Table 1. Membrane association of the parental DNA of these mutants in λ lysogens was examined essentially according to...