Identification of a gene, tir of R100, functionally homologous to the F3 gene of F in the inhibition of RP4 transfer.

We detected a gene of R100 functionally homologous to the F3 gene of F in the inhibition of RP4 transfer. Using in vitro recombinant DNA techniques, we located the gene, designated tir, in a 0.9 kb region, 2,392-3,293 in the nucleotide sequence coordinate of R100. From the DNA sequence analysis of R100 (Ohtsubo unpublished results), a coding frame of polypeptides, whose molecular weight is estimated to be 24.1 kilodaltons (kd), was inferred to be the region tir. Furthermore, we showed that tir could not repress expression of the F3 gene.