Positive regulation of minichromosome maintenance gene expression, DNA replication, and cell transformation by a plant retinoblastoma gene.
Proc Natl Acad Sci U S A
; 106(10): 4042-7, 2009 Mar 10.
Article
em En
| MEDLINE
| ID: mdl-19234120
ABSTRACT
Retinoblastoma-related (RBR) genes inhibit the cell cycle primarily by repressing adenovirus E2 promoter binding factor (E2F) transcription factors, which drive the expression of numerous genes required for DNA synthesis and cell cycle progression. The RBR-E2F pathway is conserved in plants, but cereals such as maize are characterized by having a complex RBR gene family with at least 2 functionally distinct members, RBR1 and RBR3. Although RBR1 has a clear cell cycle inhibitory function, it is not known whether RBR3 has a positive or negative role. By uncoupling RBR3 from the negative regulation of RBR1 in cultured maize embryos through a combination of approaches, we demonstrate that RBR3 has a positive and critical role in the expression of E2F targets required for the initiation of DNA synthesis, DNA replication, and the efficiency with which transformed plants can be obtained. Titration of endogenous RBR3 activity through expression of a dominant-negative allele with a compromised pocket domain suggests that these RBR3 functions require an activity distinct from its pocket domain. Our results indicate a cell cycle pathway in maize, in which 2 RBR genes have specific and opposing functions. Thus, the paradigm that RBR genes are negative cell cycle regulators cannot be considered universal.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Plantas
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Genes do Retinoblastoma
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Regulação da Expressão Gênica de Plantas
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Zea mays
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Cromossomos de Plantas
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Replicação do DNA
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
2009
Tipo de documento:
Article