Leitourgikes kai gonidiomatikes meletes epi tes apoadenulioses: o rolos tou gonidiou PNLDC1
Gene expression in eukaryotes is controlled in many levels including mRNA translation and decay. Both translation and mRNA stability are in general controlled by modulation of the mRNA's poly(A) tail length. In the majority of the mRNAs, degradation also begins with the shortening of the poly(A) tail and subsequent degradation by the cytoplasmic exosome in a 3' 5' direction or by removal of the 5' cap structure by a decapping enzyme. Shortening of poly(A) (termed deadenylation) is carried out by a variety of 3' 5' exoribonucleases known as deadenylases. Deadenylases are Mg2+ dependent 3' 5' exoribonucleases that belong to one of two superfamilies, the DEDD type or the exonuclease endonuclease phosphatase (EEP) type. DEDD type nucleases contain three conserved Asp and one Glu residue, which form the active site and coordinate the Mg2+ that support enzymatic activity. E omada aute perilambanei ten POP2, ten CAF1Z, ten PAN2 kai ten poly(A) specific ribonuclease (PARN) This group includes POP2, CAF1Z, PAN2 and poly(A) specific ribonuclease (PARN) Herein we study the gene PNLDC1 that has been found to encode a novel deadenylase that is present in higher eukaryotes. PNLDC1 promoter is methylated whereas demethylation led to detectable expression in HEK293 cells. Both PNLDC1 isoforms that are produced through alternative splicing were studied. The biochemical characterization results showed similar activity and specificity with PARN, whereas both isoforms are located in the cytoplasm and mainly in the ER. Studies on the genes expression in various mouse tissue types, as well as cell lines revealed major expression of Pnldc1 in embryonic stem cells and gametes indicating a possible role during development. Silencing of the gene in mouse embryonic stem cells showed a deregulation of major pluripotency and differentiation factors. This observation indicates a central role during early development. In silico analyses through homology modeling and molecular dynamic simulation showed that PNLDC1 has a similar active site with the DEDD deadenylases and is a new member of the mRNA surveillance and turnover repertoire. The fact that it exhibits strict epigenetic regulation, and specific subcellular localization is remarkable and has elusive so far physiological role which is currently under investigation. Regulation of mRNAs fate by deadenylation is critical for many biological processes including cell cycle, cellular response, oogenesis, spermatogenesis, early development and differentiation. Moreover, miRNA interference can trigger translational repression and mRNA degradation through deadenylation, emphasizing the unique role of this process in post transcriptional gene silencing.