| Title: |
Thymine-rich single-stranded DNA activates Mcm4/6/7 helicase on Y-fork and bubble-like substrates. |
| Authors: |
Zhiying You, Yukio Ishimi, Takeshi Mizuno, Kaoru Sugasawa, Fumio Hanaoka, Hisao Masai |
| Source: |
EMBO Journal; 11/17/2003, Vol. 22 Issue 22, p6148, 13p |
| Subject Terms: |
DNA, ADENINE, THYMINE, ADENOSINE triphosphatase |
| Abstract: |
The presence of multiple clusters of runs of asymmetric adenine or thymine is a feature commonly found in eukaryotic replication origins. Here we report that the helicase and ATPase activities of the mammalian Mcm4/6/7 complex are activated specifically by thymine stretches. The Mcm helicase is specifically activated by a synthetic bubble structure which mimics an activated replication origin, as well as by a Y-fork structure, provided that a single-stranded DNA region of sufficient length is present in the unwound segment or 3′ tail, respectively, and that it carries clusters of thymines. Sequences derived from the human lamin B2 origin can serve as a potent activator for the Mcm helicase, and substitution of its thymine clusters with guanine leads to loss of this activation. At the fork, Mcm displays marked processivity, expected for a replicative helicase. These findings lead us to propose that selective activation by stretches of thymine sequences of a fraction of Mcm helicases loaded onto chromatin may be the determinant for selection of initiation sites on mammalian genomes. [ABSTRACT FROM AUTHOR] |
|
Copyright of EMBO Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) |
| Database: |
Complementary Index |
