Functions of the Snf2/Swi2 family Rad54 motor protein in homologous recombination

Abstract

Homologous recombination is a central pathway to maintain genomic stability and is involved in the repair of DNA damage and replication fork support, as well as accurate chromosome segregation during meiosis. Rad54 is a dsDNA-dependent ATPase of the Snf2/Swi2 family of SF2 helicases, although Rad54 lacks classical helicase activity and cannot carry out the strand displacement reactions typical for DNA helicases. Rad54 is a potent and processive motor protein that translocates on dsDNA, potentially executing several functions in recombinational DNA repair. Rad54 acts in concert with Rad51, the central protein of recombination that performs the key reactions of homology search and DNA strand invasion. Here, we will review the role of the Rad54 protein in homologous recombination with an emphasis on mechanistic studies with the yeast and human enzymes. We will discuss how these results relate to in vivo functions of Rad54 during homologous recombination in somatic cells and during meiosis.

NAP1 Family Histone Chaperones Are Required for Somatic Homologous Recombination in Arabidopsis

“…The RAD51 protein binds to the ends of the DNA break to form RAD51 single-stranded DNA nucleoprotein filaments and is involved in strand invasion in HR. The RAD54 protein, a member of the SWI2/SNF2 family of ATP-dependent chromatin remodeling factors, plays diverse roles throughout HR processes, including stabilization of nucleoprotein filaments, facilitation of D-loop formation, and heteroduplex extension (Ceballos and Heyer, 2011;Knoll and Puchta, 2011). Our analyses show that expression of BRCA1, RAD51, and RAD54 is unaffected in nrp1-1 nrp2-1, excluding the hypothesis that NRPs regulate HR through transcriptional control of these key genes.…”

“…Indeed, DSB can cause a loss of nucleosomes within a few kilobases of the break (Tsukuda et al, 2005). HR is one of the two major pathways involved in repair of DSBs, but only a few factors involved in chromatin structure manipulation have been so far identified as playing a role in HR (Ransom et al, 2010;Avvakumov et al, 2011;Ceballos and Heyer, 2011;Lukas et al, 2011). HR events occur spontaneously and broadly throughout the genome; hence, it is difficult to monitor and detect HR products.…”

The Recombinases DMC1 and RAD51 Are Functionally and Spatially Separated during Meiosis in Arabidopsis

“…The yeast Swi/Snf2-remodelling factors Rad54 and Tid1/Rdh54 specifically promote strand exchange reactions of Rad51 and Dmc1, respectively (Shinohara et al, 2000;Niu et al, 2009;Mazin et al, 2010;Ceballos and Heyer, 2011). Several members of this family can be found in the genome of Arabidopsis, but so far none of them has been found to be required for meiosis (P. Schlögelhofer, unpublished data).…”

Rad54B serves as a scaffold in the DNA damage response that limits checkpoint strength

“…Rad54B and Rad54 belong to a subfamily of doublestranded DNA-dependent ATPases referred to as the SWI2/SNF2 family, which is characterized by conserved helicase-like sequence motifs 5 . Although previous studies suggested that Rad54B plays roles in the HR and DNA repair processes [6][7][8][9] , biochemical analysis has shown that Rad54B is a less active DNA-dependent ATPase than Rad54 (ref.…”