The mammalian Rad51 protein is involved in homologous recombination and in DNA damage repair. Its nuclear distribution after DNA damage is highly dynamic, and distinct foci of Rad51 protein, distributed throughout the nuclear volume, are induced within a few hours after gamma irradiation; these foci then coalesce into larger clusters. Rad51-positive cells do not undergo DNA replication. Rad51 f...

The Rb/E2F pathway plays a critical role in the control ofcellular proliferation. Here, we report that E2F1, E2F2, and E2F3 make major individual contributions toward the in vivo phenotypic consequences of Rb deficiency. In the developing lens of Rb(-/-) embryos, loss of E2F1, E2F2, or E2F3 reduces the unscheduled proliferation of fiber cells, with the loss of E2F3 having the most pronounced ef...

Replication protein A (RP-A) is involved in DNA replication, repair and recombination. It has been demonstrated that RP-A clusters in foci prior to DNA replication and redistributes over chromatin during S-phase. Here, we show that RP-A foci also form in response to DNA double-strand (ds) breaks produced on Xenopus laevis sperm nuclei by restriction enzymes and then reconstituted with Xenopus e...

Mice of the hybrid strain BC3F1 /Cum (C57BL/Cum x C3H/ AnfCum) were chronically exposed to measured amounts of machine-generated whole Kentucky reference 2A1 cigarette smoke. DNA replication and unscheduled DMA synthesis (UDS) were measured in lung tissue in vitro using a short-term organ culture method. Within one week of beginning smoke exposure, DNA replicative activity, as indicated by inco...

Removal of alkylation products from the DNA of mammalian cells was studied in nondividing human lymphocytes damaged with 7-bromomethylbenz(a)anthracene, a carcinogenic alkylating agent that produces chemically stable products upon reaction with DNA. The reaction of 7-bromomethylbenz(a)anthracene-3 H with cells in lymphocyte culture was complete in about 20 mm. The unlabeled compound induced uns...