Embryology Research Today is a free monthly online journal that collates and summarizes the latest research about Embryology, including details on stem cells, reproduction, transplants, cloning.

Establishment and maintenance of H19 imprinting in the germline and preimplantation embryo.

Reese KJ, Bartolomei MS

Howard Hughes Medical Institute, Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA.

The mouse H19 and Igf2 genes are oppositely imprinted and share enhancers that reside 3' to the genes. The imprinted expression of these genes is coordinated by a 2-kb regulatory element, the differentially methylated domain (DMD), positioned between the two genes. The methylation status of this region determines the ability of the insulator factor CTCF to bind to its sites in the DMD. Deletions and mutations of the DMD that affect imprinting in the soma have little effect on the methylation pattern of H19 in the germline, suggesting that additional sequences and factors contribute to the earliest stages of imprinting regulation at this locus. Less is known about these initial steps, which include the marking of the parental alleles, the onset of allele-specific expression patterns and maintenance of the imprints in the preimplantation embryo. Here, we will focus on these early steps, summarizing what is known and what questions remain to be addressed.

Published 31 March 2006 in Cytogenet Genome Res, 113(1): 153-8.
Full-text of this article is available online (may require subscription).

© 2005-2008 Embryology Research Today. All Rights Reserved.