Regulation of imprinting: A multi-tiered process.
Although most mammalian genes are expressed from both alleles, there is a small group of special genes which are imprinted so that only one of the parental alleles is actually expressed in target cells. This epigenetic process involves regulation at a number of different stages of development and is very complex. In principle, imprinted gene regions must be marked in cis in the gametes using epigenetic features capable of being maintained through cell division and able to direct multigenic monoallelic expression in differentiated cells of the mature organism. The difference between alleles must be erased during early gametogenesis to allow the imprint to be reset in the mature gametes. In this review we will summarize what is currently known about the molecular mechanisms which mediate these steps.
Rand
Eyal
E
Department of Cellular Biochemistry, The Hebrew University Medical School, Jerusalem, Israel 91120.
Cedar
Howard
H
D000483:Alleles; D000818:Animals; D019175:DNA Methylation; D005260:Female; D005718:Gametogenesis; D018507:Gene Expression Regulation, Developmental; D018392:Genomic Imprinting; D006801:Humans; D008297:Male; D016372:RNA, Antisense / Q000235:genetics
D016372:RNA, Antisense