DNase I footprinting analysis of RecA protein polymerized on DNA during strand exchange reaction between a gapped circle and a linear duplex.

RecA protein mediates homologous pairing and strand exchange reactions between a circular duplex with a single strand gap and a linear duplex. We have used the DNase I footprinting method to analyze processes involving four strands during these reactions. We asked how the length of DNA protected by RecA protein changes as these reactions proceed.

RecA-ssDNA interaction: induced strand cleavage by hydroxyl radical at a defined distance from the 5' end.

Interaction of the RecA protein with single-stranded DNA (ssDNA) was analyzed by challenge with the hydroxyl radical, which can cleave the DNA backbone. We found that RecA protein induces cleavage by the radical at a defined distance from the 5' end. The cleavage was at the 11th nucleotide in many oligodeoxynucleotides.

Proteins induced by DNA-damaging agents in cultured Drosophila cells.

In Drosophila cultured cells, the effects of several DNA-damaging agents on the expression of proteins were investigated. Poly(A+) RNA prepared from both untreated cells and cells treated with DNA-damaging agents was translated in vitro. The translation products were analyzed by two-dimensional electrophoresis.