A gene trap Dissociation insertion line, associated with a RING-H2 finger gene, shows tissue specific and developmental regulated expression of the gene in Arabidopsis

Real interesting new gene (RING) finger proteins act as E3 ubiquitin-protein ligases and play critical roles in targeting the destruction of proteins of diverse functions in all eukaryotes, ranging from yeast to mammals. Arabidopsis genome contains a large number of genes encoding RING finger proteins. In this report we describe the identification of more than 40 RING-H2 finger proteins that are of small size, not more than 200 amino acids, and contain no other recognizable protein-protein interaction domain(s). We characterize RHA2b, one of these small RING-H2 finger genes. A gene trap line, SGT6304, was identified to contain a Dissociation (Ds) insertion in RHA2b gene. No RHA2b transcript was detected in the homozygous SGT6304 plants. Despite the elimination of RHA2b function, homozygous SGT6304 plants lacked detectable growth or development defects, suggesting functional redundancy of RHA2b with other RING finger genes. Expression of RHA2b was specifically active in vascular tissue and in upper pistil of inflorescence as well as in root tip and shoot apical meristem region. Potential functions of ubiquitin-proteolysis pathway in vascular formation and in fertilization are discussed.