Repressor gene finO in plasmids R100 and F: constitutive transfer of plasmid F is caused by insertion of IS3 into F finO.
Fertility factor F confers bacterial conjugation, a process which involves at least 20 tra genes. Resistance plasmids such as R100, R6-5, and R1 have homology with F in the tra region. Conjugal transfer of these plasmids is, however, repressed, while transfer of F is constitutive. Repression of R transfer is due to the existence of the two genes, called finO and finP; constitutive transfer of F is believed to be due to a lack of finO in F. In this paper, we report the identification and DNA sequence of the finO gene of R100, encoding a protein of 21,265 daltons. We show that F does actually encode finO, but the gene has been inactivated by insertion of IS3. Lederberg and Tatum (Nature [London] 158:558, 1946), who discovered sexuality in bacteria, may have had an Escherichia coli K-12 strain harboring such an finO F factor, which facilitated the generation of recombinant progeny useful for genetic analysis of bacteria and established the foundation for molecular genetics.
D000595:Amino Acid Sequence; D001483:Base Sequence; D003227:Conjugation, Genetic; D004262:DNA Restriction Enzymes; D004251:DNA Transposable Elements; D004926:Escherichia coli / Q000235:genetics*; D005144:F Factor; D005796:Genes; D005798:Genes, Bacterial; D011815:R Factors; D012097:Repressor Proteins / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*
D004251:DNA Transposable Elements; D012097:Repressor Proteins; D014157:Transcription Factors; D004262:DNA Restriction Enzymes