Postreplication repair gap filling in an Escherichia coli strain deficient in dnaB gene product.

Gaps in daughter-strand DNA synthesized after exposure of Escherichia coli E279 to ultraviolet light are filled during reincubation at 30 degrees C for 20 min. Escherichia coli E279 is phenotypically DnaB- when incubated at 43 degrees C. Cells incubated at 43 degrees C were tested for their ability to complete postreplication repair gap filling. It is concluded that the dnaB gene product is essential for postreplication repair gap filling and that the inhibition seen is not initially the result of degradation.