Disease relevance of finO

• 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 [1].

High impact information on finO

• The protein FinO represses F-plasmid conjugative transfer by facilitating interactions between the mRNA of the major F-plasmid transcriptional activator, TraJ, and an antisense RNA, FinP [2].
• The energy for FinO-catalyzed base-pair destabilization does not arise from ATP hydrolysis but appears to be supplied directly from FinO RNA binding free energy [2].
• The conjugative transfer of F-like plasmids is repressed by FinO, an RNA binding protein [3].
• Three mutant alleles, a null mutation, a sense mutation and a stop mutation, were recombined back into the R1-16 plasmid, a transfer-derepressed (finO-) variant of plasmid R1 [4].
• Previously, it has been demonstrated that FinO increases the in vivo stability of the FinP RNA in the absence of the traJ mRNA target [5].

Biological context of finO

• Differential levels of fertility inhibition among F-like plasmids are related to the cellular concentration of finO mRNA [6].
• In this paper, we report the identification and DNA sequence of the finO gene of R100, encoding a protein of 21,265 daltons [1].
• The FinOP system of F-like plasmids consists of an antisense RNA (FinP) and a 22 kDa protein (FinO) which act in concert to prevent the translation of TraJ, the positive regulator of the transfer operon [6].
• The FinO repressor of bacterial conjugation contains two RNA binding regions [7].
• Our results show that FinO is largely helical, binds to its highest affinity binding site within FinP as a monomer, and contains two distinct RNA binding regions, one of which is localized between residues 26 and 61, and a second which is localized between residues 62 and 186 [7].

Physical interactions of finO

• Using electrophoretic mobility shift assays, we have shown that FinO is an RNA-binding protein that binds to one of the two stem-loops in FinP and to its complementary structure in traJ mRNA [5].

Other interactions of finO

• Recently, FinO has been shown to extend the chemical stability of FinP in vivo in the absence of traJ mRNA [8].
• The FinO protein of IncF plasmids binds FinP antisense RNA and its target, traJ mRNA, and promotes duplex formation [5].

References