Display Settings:

Format

Send to:

Choose Destination
We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Mol Cell Biol. 2000 Jan;20(1):104-12.

Kin28, the TFIIH-associated carboxy-terminal domain kinase, facilitates the recruitment of mRNA processing machinery to RNA polymerase II.

Author information

  • 1Department of Biological Chemistry, Harvard Medical School, Boston, Massachusetts 02115, USA.

Abstract

The cotranscriptional placement of the 7-methylguanosine cap on pre-mRNA is mediated by recruitment of capping enzyme to the phosphorylated carboxy-terminal domain (CTD) of RNA polymerase II. Immunoblotting suggests that the capping enzyme guanylyltransferase (Ceg1) is stabilized in vivo by its interaction with the CTD and that serine 5, the major site of phosphorylation within the CTD heptamer consensus YSPTSPS, is particularly important. We sought to identify the CTD kinase responsible for capping enzyme targeting. The candidate kinases Kin28-Ccl1, CTDK1, and Srb10-Srb11 can each phosphorylate a glutathione S-transferase-CTD fusion protein such that capping enzyme can bind in vitro. However, kin28 mutant alleles cause reduced Ceg1 levels in vivo and exhibit genetic interactions with a mutant ceg1 allele, while srb10 or ctk1 deletions do not. Therefore, only the TFIIH-associated CTD kinase Kin28 appears necessary for proper capping enzyme targeting in vivo. Interestingly, levels of the polyadenylation factor Pta1 are also reduced in kin28 mutants, while several other polyadenylation factors remain stable. Pta1 in yeast extracts binds specifically to the phosphorylated CTD, suggesting that this interaction may mediate coupling of polyadenylation and transcription.

PMID:
10594013
[PubMed - indexed for MEDLINE]
PMCID:
PMC85066
Free PMC Article

Images from this publication.See all images (6)Free text

FIG. 1
FIG. 2
FIG. 3
FIG. 4
FIG. 5
FIG. 6
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk