In Xenopus egg extracts, DNA replication initiates preferentially at or near asymmetric AT sequences.

ABSTRACT: Previous observations led to the conclusion that in Xenopus eggs and during early development, DNA replication initiates at regular intervals but with no apparent sequence specificity. Conversely, here, we present evidence for site-specific DNA replication origins in Xenopus egg extracts. Using lambda DNA, we show that DNA replication origins are activated in clusters in regions that contain closely spaced adenine or thymine asymmetric tracks used as preferential initiation sites. In agreement with these data, AT-rich asymmetric sequences added as competitors preferentially recruit origin recognition complexes and inhibit sperm chromatin replication by increasing interorigin spacing. We also show that the assembly of a transcription complex favors origin activity at the corresponding site

SUBMITTER: Stanojcic S 

PROVIDER: S-EPMC2519731 | biostudies-literature | 2008 Sep

REPOSITORIES: biostudies-literature