Abstract
In yeast and animals, a single gene encodes eukaryotic translation initiation factor 6 (eIF6) that is involved in ribosome biogenesis. Here we show the presence of two copies of eIF6-like genes in rice and Arabidopsis genomes, which are referred to as Os-eIF6;1 and Os-eIF6;2, and At-eIF6;1 and At-eIF6;2. We found that the insertion of T-DNA into At-eIF6;1 caused embryonic lethal, but the insertion into At-eIF6;2 did not. The experiment with the yeast eif6 mutant suggested a similar molecular function of yeast eIF6 and At-eIF6;1. RT-PCR analysis revealed that the expression level of At-eIF6;1 was much higher than that of At-eIF6;2, and that the expression of only Os-eIF6;2 was inducible by ammonium nitrate treatment. These results suggest that the eIF6 genes may play distinct roles in individual plant species. The result of preliminary analysis suggested that the At-eIF6;1 promoter was active at the place where cell divisions were actively proceeding.
