RNA polymerase II (RNAPII) is a large multi-protein complex that functions as a DNA-dependent RNA polymerase, catalyzing the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates (1).
The largest subunit, RNAPII subunit B1 (Rpb1), also known as RNAPII subunit A (POLR2A), contains a unique heptapeptide sequence (Tyr1, Ser2, Pro3, Thr4, Ser5, Pro6, Ser7), which is repeated up to 52 times in the carboxy-terminal domain (CTD) of the protein (1).
This CTD heptapeptide repeat is subject to multiple post-translational modifications, which dictate the functional state of the polymerase complex.
Phosphorylation of the CTD during the active transcription cycle integrates transcription with chromatin remodeling and nascent RNA processing by regulating the recruitment of chromatin modifying enzymes and RNA processing proteins to the transcribed gene (1).
During transcription initiation, RNAPII contains a hypophosphorylated CTD and is recruited to gene promoters through interactions with DNA-bound transcription factors and the Mediator complex (1).
The escape of RNAPII from gene promoters requires phosphorylation at Ser5 by CDK7, the catalytic subunit of transcription factor IIH (TFIIH) (2).
Phosphorylation at Ser5 mediates the recruitment of RNA capping enzymes, in addition to histone H3 Lys4 methyltransferases, which function to regulate transcription initiation and chromatin structure (3,4).
After promoter escape, RNAPII proceeds down the gene to an intrinsic pause site, where it is halted by the negative elongation factors NELF and DSIF (5).
At this point, RNAPII is unstable and frequently aborts transcription and dissociates from the gene.
Productive transcription elongation requires phosphorylation at Ser2 by CDK9, the catalytic subunit of the positive transcription elongation factor P-TEFb (6).
Phosphorylation at Ser2 creates a stable transcription elongation complex and facilitates recruitment of RNA splicing and polyadenylation factors, in addition to histone H3 Lys36 methyltransferases, which function to promote elongation-compatible chromatin (7,8).
Applications:Suitable for use in Immunofluorescence, Western Blot, Immunohistochemistry, Immunocytochemistry.
Other applications not tested.
Recommended Dilution:Western Blot: 1:500-1:2000Immunohistochemistry: 1:50-1:200Immunocytochemistry: 1:50-1:200Immunofluorescence: 1:50-1:200Optimal dilutions to be determined by the researcher.
Storage and Stability:May be stored at 4°C for short-term only.
Aliquot to avoid repeated freezing and thawing.
Store at -20°C.
Aliquots are stable for 12 months after receipt.
For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.
仕様
Size：200ul
Host：rabbit
Source Antibody：human
Grade：Affinity Purified
Purity：Purified by affinity chromatography.
Form：Supplied as a liquid in PBS, pH 7.3, 0.02% sodium azide, 50% glycerol.
Specificity：Recognizes POLR2A. Species Crossreactivity: human, mouse, rat
Isotype：IgG
Calc Applications Abbrev：IC IF IHC WB
Calc Crossreactivity：Hu Mo Rt
Immunogen：Recombinant protein corresponding to human POLR2A.
