Gene duplication in trypanosomatids - two DED1 paralogs are functionally redundant and differentially expressed during the life cycle.
DED1/VAS belong to the DEAD-box family of RNA helicases that are associated with translation initiation in higher eukaryotes. Here we report on two DED1/VAS homologs that were identified in the genome of Leishmania. The two paralogs include all the domains that are typical of DEAD-box proteins and a phylogenetic analysis suggests that their duplication predates the branching of DED1 and VAS, which took place along with the appearance of early metazoans. The two Leishmania DED1 paralogs complement a yeast strain that fails to express the endogenous DED1, suggesting that they are responsible for a similar function. This is also supported by RNAi-mediated silencing experiments performed in Trypanosoma brucei. The two proteins are functionally redundant, since defects in protein synthesis and cell growth arrest were observed only when both paralogs were eliminated. A partial stage-specific specialization is observed, as LeishDED1-2 is more abundant in promastigotes, whereas expression of LeishDED1-1 increases in amastigotes. Duplication of an essential gene usually offers a safety net against mutations but in this case it also generated two proteins with stage specific expression.
Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel.
Alexandra
A
Zinoviev
Yael
Y
Akum
Tal
T
Yahav
Michal
M
Shapira
D000595:Amino Acid Sequence; D000818:Animals; D053487:DEAD-box RNA Helicases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020440:Gene Duplication; D018507:Gene Expression Regulation, Developmental; D020868:Gene Silencing; D006801:Humans; D007891:Leishmania / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D008018:Life Cycle Stages; D008969:Molecular Sequence Data; D010802:Phylogeny; D014176:Protein Biosynthesis; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry; D017422:Sequence Analysis, DNA; D014346:Trypanosoma brucei brucei / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism
D015800:Protozoan Proteins; D034741:RNA, Small Interfering; D029701:Saccharomyces cerevisiae Proteins; C492152:DED1 protein, S cerevisiae; D053487:DEAD-box RNA Helicases