Question

Order the following events:                                                         

Elongation: transcription resumes with spt5 remaining

NELF recruited

DSIF is methylated

DSIF is phosphorylated

DSIF (spt4 and spt5) recruited                                                                                          

Transcription stalls                                                                                  

Capping enzymes are recruited                                                                                       

Capping takes place

DSIF dissociates: NELF leaves with spt4.

CTD phosphorylation on serine 5

Answer 1

Followings are in Correct order

DSIF (spt4 and spt5) recruited

NELF recruited

Transcription stalls

CTD phosphorylation on serine 5

Capping enzymes are recruited

Capping takes place

DSIF is phosphorylated

DSIF is methylated

DSIF dissociates: NELF leaves with spt4.

Elongation: transcription resumes with spt5 remaining  

Steps:

The Kin28 subunit of TFIIH phosphorylates the RNAP II CTD on Ser 5.

DSIF interacts with RNAP II shortly after initiation. NELF recognizes the RNAP II–DSIF complex and stalls elongation.

This pause allows the recruitment of the capping enzyme by the CTD and DSIF (Spt5 subunit), which adds a 5-cap to the growing transcript. The activity of the capping enzyme is stimulated by both the CTD and the Spt5 subunit of DSIF.

NELF is released by the concerted action of P-TEFb phosphorylation of Spt5 (DSIF) and the CTD on Ser 2, PRMT1/5 methylation of Spt5 (DSIF), and the capping enzyme itself.

Elongation: transcription resumes with spt5 remaining