Place the events of eukaryotic transcription in the correct order 1. RNA polymer
ID: 252531 • Letter: P
Question
Place the events of eukaryotic transcription in the correct order
1. RNA polymerase disassociates from the DNA
2. TFIIH and TFIIE bind to the transcription initiation complex
3. The open complex becomes destabilized
4. TFIIB binds to the promoter and to TFIID
5. Cleavage enzymes recognize the polyA sequence and cleave mRNA
6. rNTP's base pair with DNA
7. RNA polymerase II forms phososphodiester bonds between rNTPs
8. TFIID binds to the TATA box
9. RNA polymerase transcribes the poly-A sequence
10. TFIIH disrupts hydrogen bonds between the 2 strands of DNA
11. RNA polymerase II binds to the promoter with TFII-F
12. TFIIH attached phosphate groups to the C-terminal domain of RNA polymerase II
Explanation / Answer
Ans-
During eukaryotic transcription, PIC is required for the binding promoter. The steps include:
Initiation:
1.The TATA-binding protein (TBP, a subunit of TFIID), TBPL1, or TBPL2 bind the promoter or TATA box. TBP then binds a second general transcription factor (TFIIB) forming a TBP-TFIIB complex at the promoter and forms a complex with transcription factors TFIID and TFIIA.
2. TFIIF has two subunits such as RAP30 and RAP74 and Pol II together enter the complex. where TFIIE joins the growing complex and recruits TFIIH. TFIIE and TFIIH are required for initiation of transcription.
3. TFIIH binds specifically to the template strand and ensures the correct strand of DNA is transcribed and separate the two strands by using its helicase activity. It has a kinase activity that phosphorylates the C-terminal domain (CTD) of Pol II at the amino acid serine.
Elongation:
.During elongation process, the first two rNTPs complementary to the DNA bind to the active site of RNA polymerase and the first phosphodiester bond is formed. Phosphorylation of Ser-2 causes the RNA splicing that catalyzes the removal of non-coding introns to form mature mRNA. 5’-capping and splicing, the CTD tail is involved in to recruit enzymes that responsible for 3’-polyadenylation, RNA pol II becomes destabilized after transcription of the poly A sequence.
Termination:
It is the last stage of transcription that leads to the dissociation of the complete transcript and the release of RNA polymerase from the template DNA. When RNA polymerase reaches a specific sequence of nucleotides on the DNA, a hairpin loop structure form on the RNA strand that causes the RNA polymerase and mRNA to dissociate from the DNA.