The MADS-box is a conserved DNA binding domain present in all members of a large family of transcription factors. The term MADS derives from the initials of the first four members identified (MCM1 of Saccaromyces cerevisiae, AGAMOUS of Arabidopsis thaliana , DEFICIENS of Antirrhinum majus and SRF of Homo sapiens sapiens). Based on phylogenetic reconstruction, the family was divided into two main groups, type I and type II, both present in fungi, animal and plants. Recently, the completion of the Arabidopsis genome sequence led to the identification of 107 MADS-box genes, 68 type I and 39 type II. Type I members group together with SRF-like genes and they contain no known structural domains other than the conserved MADS-box. Type II (or MIKC) MADS-box protein s posses three additional functional domains, the K-box, a coiled coil domain involved in dimerisation, the less conserved I-region (intervening) which determines selective formation of DNA-binding protein dimers, and a variable C-terminal region involved in the formation of ternary or quaternary complexes. Type II MADS-box transcription factors control several processes during plant development, including the determination of flowering time, the transition from vegetative to reproductive phase, and the identity of the floral meristems, floral organs and ovules. Additionally, they are involved in root architecture, seed development and plant aging. Interestingly, all the known mutant phenotypes are caused by disruption of type II MADS-box genes, while so far no function has been assigned to any type I gene. This is probably due to functional redundancy and/or subtle phenotypes since their expression level is very low, many can only be detected employing RT-PCR methods. This project (FRED) intends to gain functional the lack of information about the type I MADS-box genes. In particular, the aims of FRED will be the functional and molecular characterisation of those genes involved in embryo development.
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