An inactive X specific replication origin associated with a matrix attachment region in the human X linked HPRT gene
✍ Scribed by Edda Koina; Anita Piper
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- English
- Weight
- 329 KB
- Volume
- 95
- Category
- Article
- ISSN
- 0730-2312
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✦ Synopsis
Abstract
Early in female mammalian embryogenesis, one of the two X chromosomes is inactivated to compensate the gene dosage between males and females. One of the features of X chromosome inactivation (XCI) is the late replication of the inactivated X chromosome. This study reports the identification, by competitive PCR of nascent DNA, of a replication origin in intron 2 of the human X‐linked HPRT gene, that is functional only on the inactive X. Features frequently associated with replication origins, including a peak of enhanced DNA flexibility, a perfect match to the yeast ACS sequence, a 14/15 match to the Drosophila topoisomerase II consensus, and a 20/21 match to an initiation region consensus sequence, were identified close to the replication origin. The origin is located approximately 2 kb upstream of a matrix attachment region (MAR) and also contains two A:T‐rich elements, thought to facilitate DNA unwinding. © 2005 Wiley‐Liss, Inc.