RNA Transcription Eukaryotic System

Prokaryotic and eukaryotic RNA transcriptions show strong parallels though there are several important differences. A major distinction between prokaryotes and eukaryotes is the move from one prokaryotic enzyme that can faithfully transcribe DNA into RNA to three eukaryotic RNA polymerases. The eukaryotic RNA transcripts are precursors (e.g. pre-mRNA, pre-rRNA and pre-tRNA), which undergo processing to form respective mature RNAs. Furthermore, eukaryotic mRNAs are polyadenylated. A database for mammalian mRNA polyadenylation is available at PolyA DB (http // polya.umdnj.edu/polyadb). The eukaryotic transcription is tightly regulated and various proteins/factors known as transcription factors (TF) are involved in the eukaryotic transcription. The classification of transcription factors can be found at TRANFAC (http //transfac.gbf.de/TRANFAC/cl/cl.html). 

Eukaryotic cells have three distinct RNA polymerases that promotes RNA transcription. RNA polymerase I (RNAPI) is located in the nucleoli and synthesizes the precursor of major rRNAs. RNA polymerase II (RNAPII) is located in the nucleoplasm and 

TABLE 13.5 Human general transcription initiation factors for RNA polymerase II 

RNAP II 0-220 12 Catalytic synthesis of RNA transcript, recruitment of TIFF 

TIFF 12,19,35 3 Stabilization of TBD binding, stabilization of TAF-DNA interactions, anti-repression functions 

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