• Product name

    Recombinant human RNA polymerase II CTD repeat YSPTSPS protein
    See all RNA polymerase II CTD repeat YSPTSPS proteins and peptides
  • Biological activity

    1 unit equals 1 nanogram of purified protein. 20 units are sufficient for reconstituted transcription assay and 100 units are sufficient for a protein-protein interaction assay. Has been applied in in vitro transcription assays, splicing assays and protein-protein interactions assays. 

  • Purity

    > 95 % SDS-PAGE.

  • Expression system

    Escherichia coli
  • Accession

  • Protein length

    Protein fragment
  • Animal free

  • Nature

    • Species

    • Predicted molecular weight

      42 kDa
    • Amino acids

      1586 to 1951
    • Additional sequence information

      Recombinant protein isolated from E. coli strain that carries the coding seq of human RNA pol II carboxy-terminal domain under control of a T7 promoter. Heptapeptide seq Tyr-Ser-Pro-Thr-Ser-Pro-Ser.


Our Abpromise guarantee covers the use of ab81888 in the following tested applications.

The application notes include recommended starting dilutions; optimal dilutions/concentrations should be determined by the end user.

  • Applications


  • Form

  • Concentration information loading...

Preparation and Storage

  • Stability and Storage

    Shipped on dry ice. Upon delivery aliquot and store at -80ºC. Avoid freeze / thaw cycles.

    pH: 8.00
    Constituents: 0.75% Potassium chloride, 0.0154% DTT, 0.316% Tris HCl, 0.00584% EDTA, 20% Glycerol

    This product is an active protein and may elicit a biological response in vivo, handle with caution.

General Info

  • Alternative names

    • DNA directed RNA polymerase II A
    • DNA-directed RNA polymerase II largest subunit RNA polymerase II 220 kd subunit
    • DNA-directed RNA polymerase II subunit A
    • DNA-directed RNA polymerase II subunit RPB1
    • DNA-directed RNA polymerase III largest subunit
    • hRPB220
    • hsRPB1
    • POLR2
    • Polr2a
    • POLRA
    • Polymerase (RNA) II (DNA directed) polypeptide A
    • Polymerase (RNA) II (DNA directed) polypeptide A 220kDa
    • RNA polymerase II subunit B1
    • RNA-directed RNA polymerase II subunit RPB1
    • RPB1
    • RPB1_HUMAN
    • RPBh1
    • RpIILS
    • RPO2
    • RPOL2
    see all
  • Function

    DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Largest and catalytic component of RNA polymerase II which synthesizes mRNA precursors and many functional non-coding RNAs. Forms the polymerase active center together with the second largest subunit. Pol II is the central component of the basal RNA polymerase II transcription machinery. It is composed of mobile elements that move relative to each other. RPB1 is part of the core element with the central large cleft, the clamp element that moves to open and close the cleft and the jaws that are thought to grab the incoming DNA template. At the start of transcription, a single-stranded DNA template strand of the promoter is positioned within the central active site cleft of Pol II. A bridging helix emanates from RPB1 and crosses the cleft near the catalytic site and is thought to promote translocation of Pol II by acting as a ratchet that moves the RNA-DNA hybrid through the active site by switching from straight to bent conformations at each step of nucleotide addition. During transcription elongation, Pol II moves on the template as the transcript elongates. Elongation is influenced by the phosphorylation status of the C-terminal domain (CTD) of Pol II largest subunit (RPB1), which serves as a platform for assembly of factors that regulate transcription initiation, elongation, termination and mRNA processing. Acts as an RNA-dependent RNA polymerase when associated with small delta antigen of Hepatitis delta virus, acting both as a replicate and transcriptase for the viral RNA circular genome.
  • Sequence similarities

    Belongs to the RNA polymerase beta' chain family.
  • Domain

    The C-terminal domain (CTD) serves as a platform for assembly of factors that regulate transcription initiation, elongation, termination and mRNA processing.
  • Post-translational

    The tandem heptapeptide repeats in the C-terminal domain (CTD) can be highly phosphorylated. The phosphorylation activates Pol II. Phosphorylation occurs mainly at residues 'Ser-2' and 'Ser-5' of the heptapeptide repeat and is mediated, at least, by CDK7 and CDK9. CDK7 phosphorylation of POLR2A associated with DNA promotes transcription initiation by triggering dissociation from DNA. Phosphorylation also takes place at 'Ser-7' of the heptapeptide repeat, which is required for efficient transcription of snRNA genes and processing of the transcripts. The phosphorylation state is believed to result from the balanced action of site-specific CTD kinases and phosphatases, and a 'CTD code' that specifies the position of Pol II within the transcription cycle has been proposed. Dephosphorylated by the protein phosphatase CTDSP1.
    Among tandem heptapeptide repeats of the C-terminal domain (CTD) some do not match the Y-S-P-T-S-P-S consensus, the seventh serine residue 'Ser-7' being replaced by a lysine. 'Lys-7' in these non-consensus heptapeptide repeats can be alternatively acetylated, methylated and dimethylated. EP300 is one of the enzyme able to acetylate 'Lys-7'. Acetylation at 'Lys-7' of non-consensus heptapeptide repeats is associated with 'Ser-2' phosphorylation and active transcription. It may regulate initiation or early elongation steps of transcription specially for inducible genes.
    Methylated at Arg-1810 prior to transcription initiation when the CTD is hypophosphorylated, phosphorylation at Ser-1805 and Ser-1808 preventing this methylation. Symmetrically or asymmetrically dimethylated at Arg-1810 by PRMT5 and CARM1 respectively. Symmetric or asymmetric dimethylation modulates interactions with CTD-binding proteins like SMN1/SMN2 and TDRD3. SMN1/SMN2 interacts preferentially with the symmetrically dimethylated form while TDRD3 interacts with the asymmetric form. Through the recruitment of SMN1/SMN2, symmetric dimethylation is required for resolving RNA-DNA hybrids created by RNA polymerase II, that form R-loop in transcription terminal regions, an important step in proper transcription termination. CTD dimethylation may also facilitate the expression of select RNAs. Among tandem heptapeptide repeats of the C-terminal domain (CTD) some do not match the Y-S-P-T-S-P-S consensus, the seventh serine residue 'Ser-7' being replaced by a lysine. 'Lys-7' in these non-consensus heptapeptide repeats can be alternatively acetylated, methylated and dimethylated. Methylation occurs in the earliest transcription stages and precedes or is concomitant to 'Ser-5' and 'Ser-7' phosphorylation.
    Ubiquitinated by WWP2 leading to proteasomal degradation (By similarity). Following UV treatment, the elongating form of RNA polymerase II (RNA pol IIo) is ubiquitinated UV damage sites without leading to degradation: ubiquitination is facilitated by KIAA1530/UVSSA and promotes RNA pol IIo backtracking to allow access to the nucleotide excision repair machinery.
  • Cellular localization

  • Information by UniProt


ab81888 has not yet been referenced specifically in any publications.

Customer reviews and Q&As

1-5 of 5 Abreviews or Q&A


Review text: we tried to establish an lanthascreen assay using LANCE® Ultra ULight™-anti-6xHis capturing RNA polymerase II CTD repeat YSPTSPS protein (His tag) (ab81888) an detecting p(S)2or5 with ab5401 or ab 24758 and an Europium labeled a-MsIg Antibody

The fact that the protein didn't work well for me did not mean that
the abcam protein is not working at all - it is ment that i won't have a
phosphorylation of it using my specific kinase.
Sample: Human Recombinant protein

Primary antibody (in addition to 'RNA polymerase II CTD repeat YSPTSPS protein (His tag)')
Concentration: 0.1 µg/ml

Secondary antibody
Name: Non-Abcam antibody was used: LANCE® Eu-W1024 Anti-Mouse IgG
Host species: Mouse
Clonality: Monoclonal
Conjugation: Other
Dilution: 1/100

Abcam user community

Verified customer

Submitted Feb 21 2013


This is a carboxyl-terminal domain (CTD) of RNA Polymerase II with 6x His tag on its N-terminus. Molecular weight is 44 kDa.Its complete sequence is given below:



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Thank you for your inquiry.

We have only tested this protein in SDS-PAGE. We have not tested it for in-vitro assays. It doesn't have any preservative in it, but we can't guarantee this protein will be suitable since we haven't tested it.

I apologize that this information could not be more helpful. Please contact us with any other questions.

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Thank you for your inquiry.

The concentration of lot GR-68507-1 is 0.5 mg/ml.

I hope this information helps. Please contact us with any other questions.

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Thank you for contacting us.
The molecular weight is 45kDa with 6 His tags at the C-terminal end.
I hope this information is helpful to you. Please do not hesitate to contact us if you need any more advice or information.

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