Group of SP1

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).
Natural Sp1 fraction was purified from HeLa cell nuclear extract by using wheat germ agglutinin affinity chromatography (12).

The His tagged wild-type Sp1 protein (785 amino acids) was expressed in a baculovirus system and purified by using affinity chromatography and FPLC chromatography.

GST-tagged GC-box Binding Protein(270-620) was purified from  an E.coli system.

α-Sp1 is a rabbit polyclonal serum raised against human recombinant Sp1 protein generated from baculovirus system.


Affinity purified Sp1 has been used for in vitro transcriptional activation, DNase I protection and gel mobility shift assays.
The purified protein is greater than 95% homogeneous based on SDS-PAGE analysis.
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 in different lots
1x dilution buffer A: 20 mM Tris-Cl (pH 8.0), 20% Glycerol, 100 mM KCl, 1 mM DTT and 0.2 mM EDTA
 
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