N. Boudet et al., Evolution of intron/exon structure of DEAD helicase family genes in Arabidopsis, Caenorhabditis, and Drosophila, GENOME RES, 11(12), 2001, pp. 2101-2114
The DEAD box RNA helicase (RH) proteins are homologs involved in diverse ce
llular functions in all of the organisms from prokaryotes to eukaryotes. Ne
vertheless, there is a lack of conservation in the splicing pattern in the
53 Arabidopsis thaliana (AtRHs), the 32 Caenorhabditis elegans (CeRHs) and
the 29 Drosophila melanogaster (DmRHs) genes. Of the 153 different observed
intron positions, 4 are conserved between AtRHs, CeRHs, and DmRHs, and one
position is also found in RHs from yeast and human. Of the 27 different At
RH structures with introns, 20 have at least one predicted ancient intron i
n the regions coding for the catalytic domain. In all of the organisms exam
ined, we found at least one gene with most of its intron predicted to be an
cient. In A, thaliana, the large diversity in RH structures suggests that d
uplications of the ancestral RH were followed by a high number of intron de
letions and additions. The very high bias toward phase 0 introns is in favo
r of intron addition, preferentially in phase 0. Results from this comparat
ive study of the same gene family in a plant and in two animals are discuss
ed in terms of the general mechanisms of gene family evolution.