High impact information on GA4H

• Using RNA gel blot analyses, we studied the regulation of two Arabidopsis genes, GA4 and GA4H (for GA4 homolog), both of which encode GA 3beta-hydroxylases that catalyze the final biosynthetic step to produce bioactive GAs [1].
• We describe the isolation of the Le gene of pea, which controls internode elongation and originally was described by Mendel. Heterologous screening of a pea cDNA library yielded a partial clone that was 61% identical to coding regions of the putative Arabidopsis gibberellin 3 beta-hydroxylase gene, GA4 [2].
• Spatial expression patterns of the AtABA2 and AAO3 genes, responsible for last two steps of ABA biosynthesis, were distinct from that of the GA biosynthesis gene, AtGA3ox2, in both imbibed and developing seeds, suggesting that biosynthesis of ABA and GA in seeds occurs in different cell types [3].
• Finally, we show that the FUS3 protein physically interacts with two RY elements (CATGCATG) present in the AtGA3ox2 promoter [4].
• AtGA3ox2, a key gene responsible for bioactive gibberellin biosynthesis, is regulated during embryogenesis by LEAFY COTYLEDON2 and FUSCA3 in Arabidopsis [4].

Other interactions of GA4H

• In contrast to the GA4 gene, the GA4H gene was not regulated by the feedback inhibition mechanism in germinating seeds [1].

References