Why a Constant Number of Vertebrae? Digital Control of Segmental Identity during Vertebrate Development: The Somite Cycle Controls a Digital, Chromatin-Based Counter That Defines Segmental Identity and Body Plans in Vertebrate Animals.
Bioessays
; 42(1): e1900133, 2020 01.
Article
em En
| MEDLINE
| ID: mdl-31755133
ABSTRACT
It is not understood how the numbers and identities of vertebrae are controlled during mammalian development. The remarkable robustness and conservation of segmental numbers may suggest the digital nature of the underlying process. The study proposes a mechanism that allows cells to obtain and store the segmental information in digital form, and to produce a pattern of chromatin accessibility that in turn regulates Hox gene expression specific to the metameric segment. The model requires that a regulatory element be present such that the number of occurrences of the motif between two consecutive Hox genes equals the number of segments under the control of the anterior gene. This is true for the recently discovered hydroxyl radical cleavage 3bp-periodic (HRC3) motif, associated with histone modifications and developmental genes. The finding not only allows the correct prediction of the numbers of segments using only sequence information, but also resolves the 40-year-old enigma of the function of temporal and spatial collinearity of Hox genes. The logic of the mechanism is illustrated in the attached animated video. How different aspects of the proposed mechanism can be tested experimentally is also discussed.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Coluna Vertebral
/
Proteínas de Homeodomínio
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Regulação da Expressão Gênica no Desenvolvimento
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Somitos
/
Padronização Corporal
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
Bioessays
Assunto da revista:
BIOLOGIA
/
BIOLOGIA MOLECULAR
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Estados Unidos