Abstract
The HAP complex is conserved among eukaryotes and consists of three subunits, HAP2, HAP3 and HAP5. Yeast and animals have a single gene for each subunit, whereas plants have multiple genes for each subunit. We have been trying to understand diversity and multiplicity of plant HAP genes through functional analyses of each gene and complex focussing on the rice HAP3 genes. We identified ten HAP2, eleven HAP3 and nine HAP5 genes in rice and showed that three of the HAP3 genes regulate chloroplast biogenesis. Here, we show that overexpression of OsHAP3E resulted in dwarfism, erected lamina joint and abnormal panicle development. Antisense plants showed slight elongation. Several brassinosteroid-related genes and MADS-box genes were affected in the overexpressors. These results suggest that OsHAP3E may be involved in brassinosteroid-related function and panicle development. Yeast two-hybrid analysis showed specificity of interaction between HAP3 subunits and HAP5 subunits.
