Regulation of imprinting in clusters: noncoding RNAs versus insulators.
Adv Genet
; 61: 207-23, 2008.
Article
em En
| MEDLINE
| ID: mdl-18282507
ABSTRACT
Genomic imprinting is an epigenetic mechanism of transcriptional regulation through which expression of a subset of mammalian genes is restricted to one parental allele. An intriguing characteristic of imprinted genes is that they often cluster in megabase-sized chromosomal domains, indicating that domain-specific mechanisms regulate imprinting. Detailed study of the known imprinted domains has revealed a number of common characteristics. First, all clusters have an imprinting control region (ICR) that is typically 1-5 kb in size and differentially methylated, and that regulates imprinting across the entire domain. Second, the clusters have at least one noncoding RNA (ncRNA) that is usually expressed from the maternal allele and multiple paternally expressed protein-coding genes. Finally, the clusters are likely regulated by one of two mechanisms, transcription of a long ncRNA that silences expression of protein-coding genes bidirectionally in cis and blocking of shared enhancer elements by CCCTC binding factor (CTCF) binding insulators. More recent experiments may even suggest that both mechanisms operate at some clusters. In this chapter, we will describe what is known about imprinting at five well-studied imprinted loci and highlight some of the critical experiments that are required before a full understanding of imprinting mechanisms is achieved.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Família Multigênica
/
Impressão Genômica
/
RNA não Traduzido
/
Elementos Isolantes
Tipo de estudo:
Prognostic_studies
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Adv Genet
Ano de publicação:
2008
Tipo de documento:
Article
País de afiliação:
Estados Unidos