Molecular Mechanisms of Facultative Heterochromatin Formation: An X-Chromosome Perspective.
Annu Rev Biochem
; 89: 255-282, 2020 06 20.
Article
em En
| MEDLINE
| ID: mdl-32259458
ABSTRACT
Facultative heterochromatin (fHC) concerns the developmentally regulated heterochromatinization of different regions of the genome and, in the case of the mammalian X chromosome and imprinted loci, of only one allele of a homologous pair. The formation of fHC participates in the timely repression of genes, by resisting strong trans activators. In this review, we discuss the molecular mechanisms underlying the establishment and maintenance of fHC in mammals using a mouse model. We focus on X-chromosome inactivation (XCI) as a paradigm for fHC but also relate it to genomic imprinting and homeobox (Hox) gene cluster repression. A vital role for noncoding transcription and/or transcripts emerges as the general principle of triggering XCI and canonical imprinting. However, other types of fHC are established through an unknown mechanism, independent of noncoding transcription (Hox clusters and noncanonical imprinting). We also extensively discuss polycomb-group repressive complexes (PRCs), which frequently play a vital role in fHC maintenance.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Cromossomo X
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Heterocromatina
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Impressão Genômica
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Regulação da Expressão Gênica no Desenvolvimento
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Inativação do Cromossomo X
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Proteínas do Grupo Polycomb
Limite:
Animals
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Female
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Humans
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Male
Idioma:
En
Revista:
Annu Rev Biochem
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
França