Where is RNA polymerase found in eukaryotes?
Each eukaryotic polymerase also requires a distinct set of transcription factors to bring it to the DNA template. RNA polymerase I is located in the nucleolus, a specialized nuclear substructure in which ribosomal RNA (rRNA) is transcribed, processed, and assembled into ribosomes (Table 1).
Where does RNA transcription occur in eukaryotes?
Eukaryotic transcription is carried out in the nucleus of the cell by one of three RNA polymerases, depending on the RNA being transcribed, and proceeds in three sequential stages: Initiation. Elongation. Termination.
What does RNA polymerase bind to in eukaryotes?
Like prokaryotic cells, the transcription of genes in eukaryotes requires the action of an RNA polymerase to bind to a DNA sequence upstream of a gene in order to initiate transcription.
Where does RNA polymerase work in prokaryotes?
During elongation, the prokaryotic RNA polymerase tracks along the DNA template, synthesizes mRNA in the 5′ to 3′ direction, and unwinds and rewinds the DNA as it is read.
Where does the RNA polymerase bind?
To begin transcribing a gene, RNA polymerase binds to the DNA of the gene at a region called the promoter.
Where does mRNA Editing occur in a eukaryotic cell?
RNA editing has been observed in some tRNA, rRNA, mRNA, or miRNA molecules of eukaryotes and their viruses, archaea, and prokaryotes. RNA editing occurs in the cell nucleus and cytosol, as well as within mitochondria and plastids.
How does transcription take place in eukaryotic cells?
In eukaryotes, transcription and translation take place in different cellular compartments: transcription takes place in the membrane-bounded nucleus, whereas translation takes place outside the nucleus in the cytoplasm. In prokaryotes, the two processes are closely coupled (Figure 28.15).
Do eukaryotes use RNA polymerase?
Eukaryotic cells contain three distinct nuclear RNA polymerases that transcribe different classes of genes (Table 6.1). Protein-coding genes are transcribed by RNA polymerase II to yield mRNAs; ribosomal RNAs (rRNAs) and transfer RNAs (tRNAs) are transcribed by RNA polymerases I and III.
Where does transcription occur in prokaryotes and eukaryotes?
Prokaryotic transcription occurs in the cytoplasm alongside translation. Prokaryotic transcription and translation can occur simultaneously. This is impossible in eukaryotes, where transcription occurs in a membrane-bound nucleus while translation occurs outside the nucleus in the cytoplasm.
What is the role of RNA polymerase in eukaryotes?
RNA polymerase (RNAP) is the enzyme responsible for transcription in eukaryotic cells. Unlike bacterial cells where a single RNAP facilitates transcription, there are three types of RNAP in eukaryotes which play different roles in gene expression.
Where are the three subunits of RNA polymerase located?
These three structures are located in the nucleus of the enzyme, while the σ subunit is further away, and is called the sigma factor. The complete enzyme – or holoenzyme – has a total weight close to 480,000 daltons. The structure of RNA polymerase is widely variable, and depends on the group studied.
Are there any genes that are RNA polymerases?
Although the previous statement is true, there are also genes whose final product is an RNA (and not a protein), or they are genes involved in the regulation of expression. There are three types of polymerases, designated as I, II and III. We will describe its functions below:
How is RNA polymerase similar to that of archaea?
However, the RNA polymerase of archaea is very similar to the structure of polymerase in eukaryotes. They present a TATA box and transcription factors, TBP and TFIIB, specifically. In general terms, the transcription process in eukaryotes is quite similar to that found in archaea.