Homo sapiens Raw sequence reads. Homo sapiens

Human embryonic stem cells (hESCs) are pluripotent cells having unique capacity to self-renew and differentiate into all specialized cell types found in somatic tissues. However, the mechanisms underlying the unique property of pluripotency are still not completely understood. In eukaryotic cells three DNA directed RNA polymerases, Polymerases I, II, and III (Pol I-III), regulate transcription of different sets of target genes. Pol III regulates transcription of structural RNAs (tRNAs and 5S rRNAs) and several small non-protein-coding RNAs (ncRNA) including miRNAs. Pol III, as Pol I and Pol II, is composed of multiple subunits of which POLR3G (DNA directed RNA polymerase III subunit, RPC32, RPC7) is a Pol III specific subunit with no counterpart in Pol I or Pol II. POLR3G subunit is needed for transcriptional initiation of Pol III, thus being important for the proper function of this polymerase. Intriguingly, consistent with previous studies, our data show that POLR3G is highly expressed in pluripotent stem cells and is required for maintenance of pluripotent state. However, the mechanisms how POLR3G contributes to maintenance of stem cell state and its targets in stem cells are not well known. To explore the function of POLR3G in stem cells we have carried out deep transcriptome analysis of mRNAs and smallRNAs present in hESCs and regulated in a POLR3G dependent manner.