Biology Reference
In-Depth Information
TABLE I
C
OMPARISON OF
D
OUBLE
-S
TRAND
B
REAK
R
EPAIR
(DSBR) F
ACTORS IN
B
UDDING
Y
EAST AND
H
UMANS
HR repair process
Budding yeast
Humans
5
0
Resection
Mre11-
Rad50
-Xrs2 (MRX)
Exo1
Dna2
Sae2
Sgs1-Top3-RmiI
RPA
MRE11-RAD50-NBS1(MRN)
EXO1
DNA2
CtIP
BLM-TOP3
a
-RMII-RMI2
RPA
Presynapsis and synapsis
Rad52
Rad51
Rad55-Rad57
Rad54
Dmc1
BRCA2
RAD51
RAD51B, RAD51C, RAD51D,
XRCC2, XRCC3
RAD54, RAD54B, RAD51AP1
DMC1
DNA synthesis
DNA polymerase
d
DNA polymerase
d
DNA polymerase
Z
Strand displacement
Srs2
Mph1
BLM
RTEL1
FANCM
HJ
a
dissolution
Sgs1-Top3-Rmi1
BLM-TOP3-RMI1-RMI2
HJ
a
resolution
Yen1
Mus81-Mms4
Slx1-Slx4
ResA (GEN1)
MUS81-EME1
SLX1-SLX4
Chromatin remodeling
Ino80
Swi/Snf
Swr1
RSC
INO80
SWI/SNF
SWR1
TIP60
Rad52 epistasis group in bold face.
a
Holliday junction.
A. RAD51
RAD51 is unequivocally the central component in HR pathways (
Tabl e I
). It
preserves a high sequence homology to the prototypical bacterial recombinase
RecA.
41,85,89
In eukaryotes, homologous pairing and strand exchange is primarily
mediated by RAD51.
85,89
RAD51 exists as a heptamer in solution.
90
Yeast Rad51
and human RAD51 are 43 kDa and 37 kDa in size, respectively.
91,92
The
main catalytic ATPase core region that includes the Walker A/B regions and
SSB domains are conserved among the RecA/RAD51 recombinases.
91,93-95
However, RAD51 possesses an N-terminal extension that is absent in RecA,
while in RecA a C-terminal extension is found that is not found in RAD51.
96
These extensions have been implicated as possible double-stranded DNA
(dsDNA)-binding sites.
97,98
