Alleles of the maize P gene with distinct tissue specificities encode Myb-homologous proteins with C-terminal replacements.
AUTOR(ES)
Chopra, S
RESUMO
The maize P gene is a transcriptional regulator of genes encoding enzymes for flavonoid biosynthesis in the pathway leading to the production of a red phlobaphene pigment. Multiple alleles of the P gene confer distinct patterns of pigmentation to specific floral organs, such as the kernel pericarp and cob tissues. To determine the basis of allele-specific pigmentation, we have characterized the gene products and transcript accumulation patterns of the P-wr allele, which specifies colorless pericarps and red cob tissues. RNA transcripts of P-wr are present in colorless pericarps as well as in the colored cob tissues; however, the expression of P-wr in pericarp does not induce the accumulation of transcripts from the C2 and A1 genes, which encode enzymes for flavonoid pigment biosynthesis. The coding sequences of P-wr were compared with the P-rr allele, which specifies red pericarp and red cob. The P-wr and P-rr cDNA sequences are very similar in their 5' regions. There are only two nucleotide changes that result in amino acid differences; both are outside of the Myb-homologous DNA binding domain. In contrast, the 3' coding region of P-rr is replaced by a unique 210-bp sequence in P-wr. The predicted P-wr protein has a C-terminal sequence resembling a cysteine-containing metal binding domain that is not present in the P-rr protein. These results indicate that the differential pericarp pigmentation specified by the P-rr and P-wr alleles does not result from an absence of P-wr transcripts in pericarps. Rather, the allele-specific patterns of P-rr and P-wr pigmentation may be associated with structural differences in the proteins encoded by each allele.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=161193Documentos Relacionados
- A Segmental Gene Duplication Generated Differentially Expressed myb-Homologous Genes in Maize
- Molecular cloning of the C-terminal domain of Escherichia coli D-mannitol permease: expression, phosphorylation, and complementation with C-terminal permease deletion proteins.
- Species- and tissue-specific expression of the C-terminal alternatively spliced form of the tumor suppressor p53.
- Alternatively spliced products of the maize P gene encode proteins with homology to the DNA-binding domain of myb-like transcription factors.
- Fighting cancer by disrupting C-terminal methylation of signaling proteins