RT Journal Article
SR Electronic
T1 Mcm10 functions to isomerize CMG-DNA for replisome bypass of DNA blocks
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 146837
DO 10.1101/146837
A1 Lance D. Langston
A1 Ryan Mayle
A1 Grant D. Schauer
A1 Olga Yurieva
A1 Daniel Zhang
A1 Nina Y. Yao
A1 Roxana Georgescu
A1 Michael E. O’Donnell
YR 2017
UL http://biorxiv.org/content/early/2017/06/06/146837.abstract
AB Replicative helicases of all cell types are rings that unwind DNA by steric exclusion in which the helicase ring only encircles the tracking strand, excluding the other strand outside the ring. Steric exclusion mediated unwinding enables helicase rings to bypass blocks on the strand that is excluded from the central channel. Unlike other replicative helicases, eukaryotic CMG encircles duplex DNA at a forked junction and is stopped by a block on the non-tracking (lagging) strand. This report demonstrates that Mcm10, an essential replication protein unique to eukaryotes, binds CMG and enables the replisome to bypass blocks on the non-tracking strand, implying that Mcm10 isomerizes the CMG-DNA complex to position only one strand through the central channel. A similar CMG-DNA isomerization is needed at the origin for head-to-head CMGs to bypass one another during formation of bidirectional replication forks.