RNA Polymerase II and the general transcription factors
Factor
Subunit
Yeast gene
Yeast protein
Features
RNA
Polymerase II
hRPB1
192 kDa
Contains CTD; binds DNA; involved in start site selection; b’ ortholog
hRPB2
139 kDa
Contains active site; involved in start site selection, elongation rate; b ortholog
hRPB3
35 kDa
May function with Rpb11 as ortholog of the a dimer of prokaryotic RNA polymerase
hRPB4
25 kDa
Subcomplex with Rpb7; involved in stress response
hRPB5
25 kDa
Shared with PolI, II, III; target for transcriptional activators
hRPB6
18 kDa
Shared with PolI, II, III; functions in assembly and stability
hRPB7
19 kDa
Forms subcomplex with Rpb4 that preferentially binds during stationary phase
hRPB8
17 kDa
Shared with PolI, II, III; has oligonucleotide/oligosaccharide binding domain
hRPB9
14 kDa
Contains zinc ribbon motif that may be involved in elongation; functions in start site selection
hRPB10
8 kDa
Shared with PolI, II, III
hRPB11
14 kDa
May function with Rpb3 as ortholog of the a dimer of prokaryotic RNA polymerase
hRPB12
8 kDa
Shared with PolI, II, III
TFIID
TBP
27kDa
TATA-binding protein
TAFII250
145 kDa
Involved in promoter binding, G1/S progression; histone acetyltransferase; kinase (human)
CIF150
150 kDa
Involved in promoter binding; mutations arrest in G2/M of cell cycle (yeast)
TAFII130/135
42 kDa
Involved in interactions with activators; yTAFII48 recently discovered
TAFII100
90 kDa
Mutations can cause arrest in G2/M of cell cycle (yeast)
TAFII70/80
60 kDa
Similar to histone H4; binds downstream promoter elements (DPEs) (Drosophila)
TAFII31/32
17 kDa
Similar to histone H3; interacts with p53
TAFII20
68 kDa
Similar to histone H2A
TAFII15
-
-
Similar to histone H2A; highly similar to TAFII20
TAFII28
40 kDa
Similar to histone H3; contains atypical histone fold motif seen in Spt3-like transcription factors
TAFII68
-
-
Contains consensus RNA binding domain; can bind RNA and ssDNA;
TAFII55
67 kDa
Interacts with numerous activators
-
58 kDa
Recently discovered; no homologous subunit identified in metazoans
TAFII30
23 kDa
Mutations can cause arrest in G1/S of cell cycle (human)
-
47 kDa
No homologous subunit identified in metazoans
-
30 kDa
Shared with TFIIF (yeast), no homologous subunit identified in metazoans
TAFII18
19 kDa
Similar to histone H4; contains atypical histone fold motif seen in Spt3-like transcription factors
TAFII105
-
105 kDa
B-cell specific; related to TAFII130; co-activator for NF-kappaB
TFIIA
TFIIAa
32 kDa
Involved in transcriptional coactivation; involved in stabilizing TBP-DNA interactions
TFIIAb
-
-
TFIIAa and TFIIAb result from processing of a single peptide that is homologous to Toa1.
TFIIAg
13 kDa
Involved in activator interactions, TFIIA-mediated antirepression, stabilizing TBP-DNA interactions
TFIIB
TFIIB
38 kDa
Involved in start site selection, promoter binding and promoter bending during initiation
TFIIF
RAP74
82 kDa
Makes extensive contacts with DNA to position the template during initiation
RAP30
47 kDa
Binds RNA polymerase II and suppresses non-specific DNA binding
-
27 kDa
Common component of yeast TFIID, TFIIF, and Swi/Snf; similar to ENL and AF-9 proteins
TFIIE
TFIIEa
55 kDa
Interacts with TFIIH; involved in recruitment, stimulation of TFIIH and promoter opening
TFIIEb
37 kDa
Double strand DNA binding activity
TFIIH
p62
73 kDa
Required for nucleotide excision repair; target for activators
p52
59 kDa
Required for nucleotide excision repair
MAT1
32 kDa
Required for nucleotide excision repair; MAT1/Cdk7/cyclin H form the CAK subcomplex (human)
p34
37 kDa
Required for nucleotide excision repair
XPD/ERCC2
90 kDa
5´-3´ DNA helicase; ATPase; required for DNA repair
p44
52 kDa
Required for nucleotide excision repair; involved in DNA binding and stimulation of XPD activity
XPB/ERCC3
95 kDa
3´-5´ DNA helicase; ATPase; essential for promoter opening and promoter escape
Cdk7
35 kDa
Kinase subunit of cyclin-dependent CTD kinase; Kin28 & Ccl1 form the TFIIK subcomplex(yeast)
CyclinH
45 kDa
Cyclin subunit of cyclin-dependent CTD kinase