Functional analysis of the isoforms of an ABI3-like factor of Pisum sativum generated by alternative splicing
| Autor: | Luis Franco, M. Isabel Rodrigo, Andrés P. Gagete, Marta Riera |
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| Rok vydání: | 2009 |
| Předmět: |
Gene isoform
ABI3 Physiology ABI5 Molecular Sequence Data Plant Science Biology Abscisic acid Complementary DNA Gene expression Protein Isoforms Arabidopsis thaliana Amino Acid Sequence Cloning Molecular Gene Plant Proteins Base Sequence Alternative splicing isoforms Peas food and beverages DNA-binding domain biology.organism_classification Research Papers Alternative Splicing Protein Transport ABA Biochemistry RNA splicing Protein Binding |
| Zdroj: | Journal of Experimental Botany |
| ISSN: | 1460-2431 0022-0957 |
| DOI: | 10.1093/jxb/erp038 |
| Popis: | At least seven isoforms (PsABI3-1 to PsABI3-7) of a putative, pea ABI3-like factor, originated by alternative splicing, have been identified after cDNA cloning. A similar variability had previously only been described for monocot genes. The full-length isoform, PsABI3-1, contains the typical N-terminal acidic domains and C-terminal basic subdomains, B1 to B3. Reverse transcriptase-PCR analysis revealed that the gene is expressed just in seeds, starting at middle embryogenesis; no gene products are observed in embryo axes after 18 h post-imbibition although they are more persistent in cotyledons. The activity of the isoforms was studied by yeast one-hybrid assays. When yeast was transformed with the isoforms fused to the DNA binding domain of Gal4p, only the polypeptides PsABI3-2 and PsABI3-7 failed to complement the activity of Gal4p. Acidic domains A1 and A2 exhibit transactivating activity, but the former requires a small C-terminal extension to be active. Yeast two-hybrid analysis showed that PsABI3 is able to heterodimerize with Arabidopsis thaliana ABI5, thus proving that PsABI3 is functionally active. The minimum requirement for the interaction PsABI3-AtABI5 is the presence of the subdomain B1 with an extension, 81 amino acids long, at their C-terminal side. Finally, a transient onion transformation assay showed that both the active PsABI3-1 and the inactive PsABI3-2 isoforms are localized to nuclei. Considering that the major isoforms remain approximately constant in developing seeds although their relative proportion varied, the possible role of splicing in the regulatory network of ABA signalling is discussed. |
| Databáze: | OpenAIRE |
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