- Termination sites are not as precise as in prokaryotes. This is not necessary because the RNA transcript goes through post translational processing that requires cleaving the product at specific sites.  

Eukaryotic RNA Transcription (Termination)

- Elongation proceeds 5’ -> 3’ in nucleus 

Grand Valley State University

- RNA transcription in eukaryotes differs from prokaryotes in that it has many RNA polymerases and it has a more complex control sequence.  
- Numbers of RNA Polymerases:
   - RNA polymerase 1 – synthesizes the precursor to mRNA 
   - RNAP II – synthesizes mRNA precursors 
   - RNAP III- synthesizes precursors to 5S rRNA (subunit of ribosome), tRNA, and smaller RNAs. 
   - Mitochondrial and chloroplasts RNA polymerases are also present . 
- These all recognize different promoters as well. However core promoters are the TATA box that is present 25-31 base pairs upstream of the transcription start site. 
- Enhancers – are recognized by transcription factors that attract RNA polymerase II to bind to a nearby promoter. These are important in selective gene expression. 
- Transcription factors initiation transcription by binding specifically to the promoters of DNA. This is a same process in eukaryotes and prokaryotes. 
- At the TATA box a preinitaiton complex forms with the RNA polymerase transcription factors and the DNA promoter region. 
- The TATA binding protein binds to the TATA box. It forms a TFIID complex with 17 other proteins. 

Eukaryotic RNA Transcription (Initiation)

Voet, D., Voet, J. G., & Pratt, C. W. (2013). Chapter 26: Transcription and RNA Processing. In Fundamentals of biochemistry: Life at the molecular level (4th ed., pp. 919-957). Hoboken, NJ: Wiley. Retrieved April 4, 2021, from archive.org.

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