Gene expression profiles of WT and ime4-/- mutant yeast cells, under vegetative and meiosis-inducing conditions

Inactivation of the yeast IME4 gene, the yeast homologue of METTL3, was shown to result in the loss of m6A in mRNA of mutant cells grown in sporulation medium. We attempted to characterize the effects of ime4 deletion on gene expression under vegetative and meiosis-inducing conditions. The results show that in vegetatively-growing ime4-/- cells there is an increased expression of the RME1 gene (repressor of meiosis) which prevents precocious entry into the meiotic program. Mutant yeast cells showed reduced expression levels of genes involved in ribosome biogenesis and gene expression processes. Surprisingly, despite the fact that a diploid strain was analyzed, there was also a striking change in the expression level of haploid-specific genes, suggesting that RNA methylation may be used to enforce the sexual identity of diploid cells, required for the implementation of the gametogenesis program. Consistently, when cells were induced to undergo meiosis, ime4-/- diploids failed to undergo the meiotic divisions. Among the genes showing reduced expression in the mutant were IME1 and IME2, the two known inducers of meiosis. Thus, the yeast IME4 gene plays an important role in the regulation of the developmental switch from vegetative cells into gametogenesis.

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Dominissini D, Moshitch-Moshkovitz S, Schwartz S, Salmon-Divon M, Ungar L, Osenberg S, Cesarkas K, Jacob-Hirsch J, Amariglio N, Kupiec M, Sorek R, Rechavi G