SSL2/YIL143C Summary Help

Standard Name SSL2 1
Systematic Name YIL143C
Alias LOM3 , RAD25 2
Feature Type ORF, Verified
Description Component of RNA polymerase transcription factor TFIIH holoenzyme; has DNA-dependent ATPase/helicase activity and is required, with Rad3p, for unwinding promoter DNA; interacts functionally with TFIIB and has roles in transcription start site selection and in gene looping to juxtapose initiation and termination regions; involved in DNA repair; relocalizes to the cytosol in response to hypoxia; homolog of human ERCC3 (3, 4, 5, 6, 7 and see Summary Paragraph)
Name Description Suppressor of Stem-Loop mutation 1
Chromosomal Location
ChrIX:83041 to 80510 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Gene Ontology Annotations All SSL2 GO evidence and references
  View Computational GO annotations for SSL2
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 3 genes
Classical genetics
reduction of function
Large-scale survey
68 total interaction(s) for 37 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 10
  • Affinity Capture-RNA: 3
  • Affinity Capture-Western: 11
  • Biochemical Activity: 1
  • Co-crystal Structure: 1
  • Co-purification: 10
  • PCA: 8
  • Reconstituted Complex: 8
  • Two-hybrid: 4

Genetic Interactions
  • Dosage Growth Defect: 1
  • Phenotypic Suppression: 1
  • Synthetic Growth Defect: 1
  • Synthetic Lethality: 8
  • Synthetic Rescue: 1

Expression Summary
Length (a.a.) 843
Molecular Weight (Da) 95,340
Isoelectric Point (pI) 5.97
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrIX:83041 to 80510 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Last Update Coordinates: 1994-12-10 | Sequence: 1994-12-10
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..2532 83041..80510 1994-12-10 1994-12-10
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
External Links All Associated Seq | E.C. | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000001405

In S. cerevisiae, nucleotide excision repair (NER) is mediated by Rad1p, Rad2p, Rad4p, Rad7p, Rad10p, Rad14p, Rad16p, Met18p, the transcription factor TFIIH, and the heterotrimeric complex RPA (Rfa1p, Rfa2p, Rfa3p). Together these proteins bind DNA lesions, including UV-induced photoproducts and chemical crosslinks, unwind the surrounding duplex, and make incisions on both sides of the damaged DNA, which releases a fragment of 25-30bp (reviewed in 8, 9).

The DNA helicases Rad3p and Ssl2p are required for transcription and are involved in the incision step that occurs at the site of damage during NER (10, 11, 12, 13, 14). These diverse roles are carried out by their membership in two complexes: the transcription factor TFIIH and the nucleotide excision factor 3 (NEF3) (15, 16, 5). RAD3 and SSL2 are essential for viability (17, 2). However, a variety of mutations have been made to study the individual contribution of Rad3p and Ssl2p to transcription and NER. A mutation in the nucleotide binding motif of Rad3p does not affect its viability while a similar mutation in Ssl2p is lethal, suggesting the helicase activity of Rad3p is not neccessary for transcription (18, 2). In addition, mutations have been identified in RAD3 and SSL2 that do not affect viability but result in sensitivity (18, 2, 1).

In addition to its role in NER and transcription, Ssl2p has also been implicated in mRNA export from the nucleus (19). Overexpression of Ssl2p confers resistance to the chemotherapeutic drug adriamycin, providing insight into how cancer cells develop resistance to this drug (20, 21).

Ssl2p is related to H. sapiens XPB, also known as ERCC3, which is mutated in patients with xeroderma pigmentosum (XP) and Cockayne's syndrome (2). These disease are collectively known as xeroderma pigmentosum complementation group B. Deletion of the carboxy terminus of S. cerevisiae Ssl2p, which mimics the mutation found in a patient with XP, confers sensitivity to UV (1).

Last updated: 2007-11-07 Contact SGD

References cited on this page View Complete Literature Guide for SSL2
1) Gulyas KD and Donahue TF  (1992) SSL2, a suppressor of a stem-loop mutation in the HIS4 leader encodes the yeast homolog of human ERCC-3. Cell 69(6):1031-42
2) Park E, et al.  (1992) RAD25 (SSL2), the yeast homolog of the human xeroderma pigmentosum group B DNA repair gene, is essential for viability. Proc Natl Acad Sci U S A 89(23):11416-20
3) Feaver WJ, et al.  (1993) Dual roles of a multiprotein complex from S. cerevisiae in transcription and DNA repair. Cell 75(7):1379-87
4) Sweder KS and Hanawalt PC  (1994) The COOH terminus of suppressor of stem loop (SSL2/RAD25) in yeast is essential for overall genomic excision repair and transcription-coupled repair. J Biol Chem 269(3):1852-7
5) Svejstrup JQ, et al.  (1995) Different forms of TFIIH for transcription and DNA repair: holo-TFIIH and a nucleotide excision repairosome. Cell 80(1):21-8
6) Goel S, et al.  (2012) Mechanism of start site selection by RNA polymerase II: interplay between TFIIB and Ssl2/XPB helicase subunit of TFIIH. J Biol Chem 287(1):557-67
7) Ghosh Dastidar R, et al.  (2012) The nuclear localization of SWI/SNF proteins is subjected to oxygen regulation. Cell Biosci 2(1):30
8) Prakash S and Prakash L  (2000) Nucleotide excision repair in yeast. Mutat Res 451(1-2):13-24
9) Hoeijmakers JH  (1993) Nucleotide excision repair I: from E. coli to yeast. Trends Genet 9(5):173-7
10) Sung P, et al.  (1987) RAD3 protein of Saccharomyces cerevisiae is a DNA helicase. Proc Natl Acad Sci U S A 84(24):8951-5
11) Qiu H, et al.  (1993) The Saccharomyces cerevisiae DNA repair gene RAD25 is required for transcription by RNA polymerase II. Genes Dev 7(11):2161-71
12) Guzder SN, et al.  (1994) DNA repair gene RAD3 of S. cerevisiae is essential for transcription by RNA polymerase II. Nature 367(6458):91-4
13) Guzder SN, et al.  (1994) RAD25 is a DNA helicase required for DNA repair and RNA polymerase II transcription. Nature 369(6481):578-81
14) Sung P, et al.  (1996) Reconstitution of TFIIH and requirement of its DNA helicase subunits, Rad3 and Rad25, in the incision step of nucleotide excision repair. J Biol Chem 271(18):10821-6
15) Habraken Y, et al.  (1996) Transcription factor TFIIH and DNA endonuclease Rad2 constitute yeast nucleotide excision repair factor 3: implications for nucleotide excision repair and Cockayne syndrome. Proc Natl Acad Sci U S A 93(20):10718-22
16) Takagi Y, et al.  (2003) Revised subunit structure of yeast transcription factor IIH (TFIIH) and reconciliation with human TFIIH. J Biol Chem 278(45):43897-900
17) Naumovski L and Friedberg EC  (1983) A DNA repair gene required for the incision of damaged DNA is essential for viability in Saccharomyces cerevisiae. Proc Natl Acad Sci U S A 80(15):4818-21
18) Sung P, et al.  (1988) Mutation of lysine-48 to arginine in the yeast RAD3 protein abolishes its ATPase and DNA helicase activities but not the ability to bind ATP. EMBO J 7(10):3263-9
19) Mizuki F, et al.  (2007) Participation of XPB/Ptr8p, a component of TFIIH, in nucleocytoplasmic transport of mRNA in fission yeast. Genes Cells 12(1):35-47
20) Furuchi T, et al.  (2004) Overexpression of Ssl2p confers resistance to adriamycin and actinomycin D in Saccharomyces cerevisiae. Biochem Biophys Res Commun 314(3):844-8
21) Furuchi T, et al.  (2004) Functions of yeast helicase Ssl2p that are essential for viability are also involved in protection from the toxicity of adriamycin. Nucleic Acids Res 32(8):2578-85