Cap-binding translation initiation factor 4E from Candida albicans functionally complements the cdc33 mutation in Saccharomyces cerevisiae and confers temperature sensitivity to the heterologous host.
Zuzana Feketova (1), Vaclav Vopalensky (2), Tomas Masek (2), Martin Pospisek (2)
(1) Dep. of genetics and microbiology, Vinicna 5, Prague 2, 128 44 Czech Republic; (2) Dep. of genetics and microbiol, Charles University, PrfUK, Vinicna 5, Prague 2, CZ, 128 44, Czech Republic
The main function of eIF4E is recognition and binding of 7mG cap structure of eukaryotic mRNAs and consequent recruiting of the ribosome to the 5' mRNA end. The basic 5' mRNA cap structure as well as the mechanism of its recognition in the process of translation initiation seem to be well evolutionary conserved in the eukaryotic world. Surprisingly, Dunyak and co-workers prepared viable C. albicans strains lacking some of the enzymes in the 7mG cap-synthesis pathway thus producing mRNAs with modified 5' end. One of the possible explanation of their finding could be a unique and unusual feature of the C.a. eIF4E. We proved the function of putative C.a. eIF4E by its ability to complement the cdc33 mutation in S. cerevisiae. We prepared yeast strains which growth and viability were fully dependent on the expression of heterologous eIF4E from C. albicans. Interestingly, these strains reveal temperature sensitive phenotype and altered polysomal profiles. The possible explanations of this phenomenon, like improper interaction with eIF4G, differences in codon reading between S. cerevisiae and C.albicans or possible intrinsic temperature sensitivity of C.a. eIF4E will be discussed. This work was supported by GACR - Grant No. 204/03/1487, by GA UK - Grant No. 251/2004/B-BIO/PrF and by the Ministry of Education (Grant No. MSM 0021620813)Literature: Dunyak DS, Everdeen DS, Albanese JG, Quinn ChL. (2002) Eukaryot Cell. 1(6): 1010-20.