Question

Phosphorylation of the RNA Polymerase II tail: a. Transitions it from binding conformation to elongation conformation b. Results in a conformation that sequesters mRNA processing proteins c. Phosphates derived from helicase activity d. A and B but not C e. A, B, and C?

1) Transitions it from binding conformation to elongation conformation
2) Results in a conformation that sequesters mRNA processing proteins
3) Phosphates derived from helicase activity
4) A and B but not C
5) A, B, and C

Answer 1

The phosphorylation of the RNA Polymerase II tail leads to transition from binding to elongation conformation and the sequestration of mRNA processing proteins, but the phosphates are not derived from helicase activity; hence the correct option is D (A and B but not C).

Step-by-step explanation:

The phosphorylation of the RNA Polymerase II tail is pivotal in the transition of RNA Polymerase II from a binding conformation to an elongation conformation (option A). This process also results in a conformation that sequesters mRNA processing proteins (option B), facilitating the processing and maturation of mRNA. However, the phosphates involved in the phosphorylation of the RNA Polymerase II tail are not derived from helicase activity (option C), as helicase is an enzyme that unwinds DNA and does not directly contribute phosphate groups to other proteins.

During transcription, after the preinitiation complex formation, RNA Polymerase II transcribes pre-mRNA in the 5' to 3' direction. The process is essentially initiated by various transcription factors and proceeds energetically due to the breaking of the high-energy bond in the incoming NTP and the formation of a high-energy phosphodiester bond in the elongating mRNA strand. The correct option that addresses the phosphorylation events of RNA Polymerase II tail is option D (A and B but not C).