Natural Sp1 fraction was purified from HeLa cell nuclear extract by using wheat germ agglutinin affinity chromatography (12).
Unit Definition (Activity)
1 unit equals 1 nanogram of purified protein. 50-100 units (ng) are sufficient for a reconstituted transcription assay and 5-25 units (ng) are sufficient for a gel mobility shift assay in a 20μl reaction. Variable exist in different lots.
Applications
Affinity purified Sp1 has been used for in vitro transcriptional activation, DNase I protection and gel mobility shift assays.
Formulation and Storage
The protein is in 20mM Tris-HCl pH7.9,100mM NaCl, 0.2mM EDTA, 1mM DTT and 20% glycerol. Stored at -70°C before use. Avoid repeated freeze thaw cycles.
Background
Sp1 was first detected in HeLa cells on the basis of its ability to activate the SV40 early promoter transcription (1,2). Subsequently it was shown to recognize and bind selectively to a GC-rich consensus sequence (GC-box: GGGCGG or CACCC) that presents in the promoter of several important cellular genes, including SV40 early, HIV-1, PDGF-B etc. Sp1 was the first transcription factor to be cloned (3). Analysis of structure and function has revealed that Sp1 can be separated into discrete functional domains. The DNA-binding domain consists of three zinc fingers that specifically bind to the GC-box element (4,5). Sp1 contains at least four separate transcriptional activation domains. Two of these domains are glutamine-rich, a well-characterized motif found in several other transcription factors (6). In addition to transcription, Sp1 function has been linked to cell growth, cancer, Huntington disease and other disorders through transcriptional regulation or specific protein-protein interactions (7-9). The function of Sp1 can be regulated by phosphorylation and glycosylation (10,11).
References
1.Dynan, WS. et al., (1983) Cell 35, 79-87 2.Briggs, MR. et la., (1986) Science 234, 47-52 3.Kadonaga, JT. et al., (1987) Cell 51, 1079-1090 4.Pascal, E. et al., (1991) Genes & Dev. 5, 1646-1656 5.Nagaoka, M et al., (2001) Nucleic Acids Res. 29, 4920-4929 6.Tanaka, M. et al., (1990) Cell 60, 375-386 7.Black, AR. et al., (2001) J Cell. Physiol. 188, 143-160 8.Rafty, LA. et al., (2002) J Cell Biochem 85, 490-495 9.Dunah, AW. et al., (2002) Science 0, 10726131-0 10.Leggett, RW. et al., (1995) J Biol. Chem. 270, 25879-25884 11.Han, I. et al., (1997) Mol. Cell. Biol. 17, 2550-2558
12.Jackson, SP. et al., (1989) Proc. Natl. Acad. Sci. USA 86, 1781-1785
DISCLAIMER
This products is recommended For RESEARCH USE ONLY and is Not qualified for Use in Diagnostic or Therapeutic Procedures.
