engleski

THE CONTROL OF DYNAMIC TRANSCRIPT ARCHITECTURE

The sizes of many transcripts change when yeast cells exit mitosis and enter the meiotic differentiation pathway. These differences were attributed to length variations of the 5’ untranslated regions (UTR) of mRNAs. The function of UTRs in protein translation is well established. However, the mechanism controlling the expression of distinct transcript isoforms during mitotic growth and meiotic development is unknown. Based on tilling array data, we order developmentally regulated transcript isoforms according to their expression at specific stages during meiosis and gametogenesis, as compared to vegetative growth and starvation. We employ regulatory motif prediction, in vivo protein-DNA binding assays, genetic analyses and monitoring of epigenetic amino acid modification patterns to identify a novel role for Rpd3 and Ume6, two components of a histone deacetylase complex already known to repress early meiosis-specific genes in dividing cells, in mitotic repression of meiosis-specific transcript isoforms. Our findings classify developmental stage-specific early, middle and late meiotic transcript isoforms, and they point to a novel HDAC- dependent control mechanism for flexible transcript architecture during cell growth and differentiation. Since Rpd3 is highly conserved and ubiquitously expressed in many tissues, our results are likely relevant for development and disease in higher eukaryotes. The implications of these observations for the expression and stability for lncRNAs, mRNAs and proteins during meiotic development will be discussed.

meiosis, UTR

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