| Type: | Family | Name: | Late competence development protein ComFB |
| Description: | Competence is the ability of a cell to take up exogenous DNA from its environment, resulting in transformation. It is widespread among bacteria and is probably an important mechanism for the horizontal transfer of genes. DNA usually becomes available by the death and lysis of other cells. Competent bacteria use components of extracellular filaments called type 4 pili to create pores in their membranes and pull DNA through the pores into the cytoplasm. This process, including the development of competence and the expression of the uptake machinery, is regulated in response to cell-cell signalling and/or nutritional conditions [].The development of genetic competence in Bacillus subtilisis a highly regulated adaptive response to stationary-phase stress. For competence to develop, the transcriptional regulator, ComK, must be activated. ComK is required for the expression of genes encoding proteins that function in DNA uptake. In log-phase cultures, ComK is inactive in a complex with MecA and ClpC. The comS gene is induced in response to high culture cell density and nutritional stress and its product functions to release active ComK from the complex. ComK then stimulates the transcription initiation of its own gene as well as that of the late competence operons [].The comF locus has three open reading frames and is driven by a single sigma A-like promoter in front of comFORF1. It is dependent on early regulatory competence genes and is only expressed in competence medium. ComFORF1 is similar to an extensive family of ATP-dependent RNA/DNA helicases with closer similarity to the DEAD protein subfamily and to the PriA protein in Escherichia coli. ComFORF1 late gene product plays an essential role during the binding and uptake events involved in B. subtilis transformation []. ComFB is the second protein encoded within the late competence locus ComF []. The function of ComFB within late competence development is not known. | Short Name: | ComFB |
