An alternative form of replication protein a prevents viral replication in vitro.
Replication protein A (RPA), the eukaryotic single-stranded DNA-binding complex, is essential for multiple processes in cellular DNA metabolism. The "canonical" RPA is composed of three subunits (RPA1, RPA2, and RPA3); however, there is a human homolog to the RPA2 subunit, called RPA4, that can substitute for RPA2 in complex formation. We demonstrate that the resulting "alternative" RPA (aRPA) complex has solution and DNA binding properties indistinguishable from the canonical RPA complex; however, aRPA is unable to support DNA replication and inhibits canonical RPA function. Two regions of RPA4, the putative L34 loop and the C terminus, are responsible for inhibiting SV40 DNA replication. Given that aRPA inhibits canonical RPA function in vitro and is found in nonproliferative tissues, these studies indicate that RPA4 expression may prevent cellular proliferation via replication inhibition while playing a role in maintaining the viability of quiescent cells.
Mason
Aaron C
AC
Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA.
Haring
Stuart J
SJ
Pryor
John M
JM
Staloch
Cathy A
CA
Gan
Tze Fei
TF
Wold
Marc S
MS
D004261:DNA Replication / Q000502:physiology*; D004279:DNA, Viral / Q000096:biosynthesis* / Q000737:chemistry; D006367:HeLa Cells; D006801:Humans; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism*; D017434:Protein Structure, Tertiary / Q000502:physiology; D051716:Replication Protein A / Q000737:chemistry / Q000378:metabolism*; D013539:Simian virus 40 / Q000737:chemistry / Q000502:physiology*; D014779:Virus Replication / Q000502:physiology*
D004279:DNA, Viral; D046912:Multiprotein Complexes; D051716:Replication Protein A