What are the functions of RNA polymerase I II and III?

RNA polymerase I (RNAPI) transcribes rRNA genes, RNA polymerase II (RNAPII) transcribes mRNA, miRNA, snRNA, and snoRNA genes, and RNA polymerase III (RNAPIII) transcribes tRNA and 5S rRNA genes. This is in contrast with prokaryotes where a single RNA polymerase is responsible for the transcription of all genes.

What is the role of DNA polymerase 2?

DNA polymerase II is the product of polB gene and seems to play an important role in replication restart in UV-irradiated E. coli [71], can be error-prone [72] and may play a role in lesion bypass in a DNA repair pathway for inter-strand cross-links [73].

What is the role of RNA polymerase II?

Eukaryotic RNA polymerase II (pol II) is a 12-subunit DNA-dependent RNA polymerase that is responsible for transcribing nuclear genes encoding messenger RNAs and several small nuclear RNAs (1).

Why do eukaryotes have 3 RNA polymerases?

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.

What are the major differences between eukaryotic and prokaryotic RNA polymerases?

Prokaryotes have only one RNA Polymerase, while eukaryotes have three (RNA Polymerases I, which transcribes rRNA; II, which transcribes mRNA; and III, which transcribes tRNA). The difference in molecular weight between the prokaryotic polymerase and Pol II in eukaryotes is 100 kDa (400 kDa to 500 kDa).

How is RNA polymerase used in RNA?

During transcription, the information encoded in DNA is used to make RNA. RNA polymerase synthesizes RNA, using the antisense strand of the DNA as template by adding complementary RNA nucleotides to the 3′ end of the growing strand. RNA polymerase binds to DNA at a sequence called a promoter during the initiation of transcription.

What does RNA polymerase III stand for?

(April 2019) ( Learn how and when to remove this template message) In eukaryote cells, RNA polymerase III (also called Pol III) transcribes DNA to synthesize ribosomal 5S rRNA, tRNA and other small RNAs.

Which is RNA polymerase binding site on a typical gene?

The DNA sequence to which RNA polymerase binds to initiate transcription of a gene is called the promoter . The promoter is a specific site at the beginning of genes where transcription is initiated. The initiation process is important because this is the primary step at which transcription is regulated.

Where is RNA polymerase synthesized?

Almost all RNAs are synthesized in the nucleus, where segments of the DNA are transcribed into preRNA’s by elaborate molecular machines called RNA polymerases.