title: The hematopoietic transcription factor SCL binds the p44 subunit of TFIIH.
abstract: SCL is a basic domain helix-loop-helix (bHLH) oncoprotein that is involved in T-cell acute lymphoblastic leukemia as well as in normal hematopoiesis. Although it is believed that SCL functions as a tissue-specific transcription factor, no molecular mechanism has thus far been identified for this putative function. In this report, we show that SCL interacts with p44, a subunit of the basal transcription factor TFIIH. The minimal region of SCL that interacts with p44 was mapped to a 101-amino acid sequence that includes, but is not limited to, the bHLH region; the SCL-binding site of p44 is located in the carboxyl-terminal half of p44. This interaction was confirmed by glutathione S-transferase fusion protein pull-down assays and a co-immunoprecipitation assay. As analyzed with a yeast two-hybrid system, p44 interacts specifically with SCL, but not with the other class A or B bHLH proteins tested. E2A did not compete with p44 for SCL binding, as demonstrated by an in vitro binding assay. These findings document a previously unsuspected interaction between SCL and a subunit of the basal transcription factor TFIIH, suggesting a potential means by which SCL might modulate transcription.
authors.affiliation: Departments of Pediatrics and Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York 14263, USA.
authors.forename: X F
authors.initials: XF
authors.lastname: Zhao
authors.forename: P D
authors.initials: PD
authors.lastname: Aplan
mesh_terms: D002460:Cell Line; D002874:Chromosome Mapping; D004265:DNA Helicases / Q000378:metabolism*; D004260:DNA Repair; D018257:Helix-Loop-Helix Motifs; D006801:Humans; D011485:Protein Binding; D011487:Protein Conformation; D051758:Transcription Factor TFIIH; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D019473:Transcription Factors, TFII
chemical_list: D014157:Transcription Factors; D019473:Transcription Factors, TFII; D051758:Transcription Factor TFIIH; D004265:DNA Helicases