# Gene transcriptions/Sps

Specificity protein 1 is Sp1.
Sp1 has been used as a control protein to compare with when studying the increase or decrease of the aryl hydrocarbon receptor and/or the estrogen receptor, since it binds to both and generally remains at a relatively constant level.
Withaferin A, a sterodial lactone from Withania somnifera is known to inhibit Sp1 transcription factor.

## Consensus sequences

SP1 belongs to the Sp/KLF family of transcription factors. The protein is 785 amino acids long, with a molecular weight of 81 kDA. The SP1 transcription factor contains a zinc finger motif, by which it binds directly to DNA and enhances gene transcription. Its zinc fingers are of the Cys$_2$/His$_2$ type and bind the consensus sequence 5'-(G/T)GGGCGG(G/A)(G/A)(C/T)-3' (GC box).

## Human genes

GeneID: 6667 is SP1 Sp1 transcription factor. "The protein encoded by this gene is a zinc finger transcription factor that binds to GC-rich motifs of many promoters. The encoded protein is involved in many cellular processes, including cell differentiation, cell growth, apoptosis, immune responses, response to DNA damage, and chromatin remodeling. Post-translational modifications such as phosphorylation, acetylation, glycosylation, and proteolytic processing significantly affect the activity of this protein, which can be an activator or a repressor. Three transcript variants encoding different isoforms have been found for this gene."
* NP_612482.2 transcription factor Sp1 isoform a.
* NP_003100.1 transcription factor Sp1 isoform b.
* NP_001238754.1 transcription factor Sp1 isoform c.
* XP_011536998.1 transcription factor Sp1 isoform X1.
GeneID: 6668 is SP2 Sp2 transcription factor. "This gene encodes a member of the Sp subfamily of Sp/XKLF transcription factors. Sp family proteins are sequence-specific DNA-binding proteins characterized by an amino-terminal trans-activation domain and three carboxy-terminal zinc finger motifs. This protein contains the least conserved DNA-binding domain within the Sp subfamily of proteins, and its DNA sequence specificity differs from the other Sp proteins. It localizes primarily within subnuclear foci associated with the nuclear matrix, and can activate or in some cases repress expression from different promoters."
* NP_003101.3 transcription factor Sp2.
* XP_011523438.1 transcription factor Sp2 isoform X1.
* XP_011523439.1 transcription factor Sp2 isoform X2.
* XP_011523440.1 transcription factor Sp2 isoform X3.
* XP_011523441.1 transcription factor Sp2 isoform X4.
* XP_011523442.1 transcription factor Sp2 isoform X5.
* XP_006722086.1 transcription factor Sp2 isoform X6.
* XP_006722088.1 transcription factor Sp2 isoform X7.
* XP_006722089.1 transcription factor Sp2 isoform X7.
* XP_006722090.1 transcription factor Sp2 isoform X7.
* XP_011523444.1 transcription factor Sp2 isoform X7.
* XP_011523445.1 transcription factor Sp2 isoform X7.
* XP_016880457.1 transcription factor Sp2 isoform X7.
* XP_024306660.1 transcription factor Sp2 isoform X8.
Gene ID: 6670 is SP3 Sp3 transcription factor. "This gene belongs to a family of Sp1 related genes that encode transcription factors that regulate transcription by binding to consensus GC- and GT-box regulatory elements in target genes. This protein contains a zinc finger DNA-binding domain and several transactivation domains, and has been reported to function as a bifunctional transcription factor that either stimulates or represses the transcription of numerous genes. Transcript variants encoding different isoforms have been described for this gene, and one has been reported to initiate translation from a non-AUG (AUA) start codon. Additional isoforms, resulting from the use of alternate downstream translation initiation sites, have also been noted. A related pseudogene has been identified on chromosome 13."
* NP_003102.1 transcription factor Sp3 isoform 1.
* NP_001017371.3 transcription factor Sp3 isoform 2.
* NP_001166183.1 transcription factor Sp3 isoform 3.
GeneID: 6671 is SP4 Sp4 transcription factor. "The protein encoded by this gene is a transcription factor that can bind to the GC promoter region of a variety of genes, including those of the photoreceptor signal transduction system. The encoded protein binds to the same sites in promoter CpG islands as does the transcription factor SP1, although its expression is much more restricted compared to that of SP1. This gene may be involved in bipolar disorder and schizophrenia."
* NP_003103.2 transcription factor Sp4 isoform 1.
* NP_001313471.1 transcription factor Sp4 isoform 2.
* NP_001313472.1 transcription factor Sp4 isoform 3.
* NR_137166.1 RNA Sequence non-coding (variant 4).
* XP_011513788.1 transcription factor Sp4 isoform X1.
* XP_005249886.1 transcription factor Sp4 isoform X2.
* XP_016868046.1 transcription factor Sp4 isoform X3.
* XP_011513789.1 transcription factor Sp4 isoform X4.
GeneID: 389058 is SP5 Sp5 transcription factor.
* NP_001003845.1 transcription factor Sp5.
* XP_011509461.1 transcription factor Sp5 isoform X1.
* XP_005246599.1 transcription factor Sp5 isoform X2.
GeneID: 80320 is SP6 Sp6 transcription factor (aka KLF14). "SP6 belongs to a family of transcription factors that contain 3 classical zinc finger DNA-binding domains consisting of a zinc atom tetrahedrally coordinated by 2 cysteines and 2 histidines (C2H2 motif). These transcription factors bind to GC-rich sequences and related GT and CACCC boxes."
* NP_001245177.1 transcription factor Sp6 (variant 1).
* NP_954871.1 transcription factor Sp6 (variant 2).
* XP_006722178.1 transcription factor Sp6 isoform X1.
GeneID: 121340 is SP7 Sp7 transcription factor. "This gene encodes a member of the Sp subfamily of Sp/XKLF transcription factors. Sp family proteins are sequence-specific DNA-binding proteins characterized by an amino-terminal trans-activation domain and three carboxy-terminal zinc finger motifs. This protein is a bone specific transcription factor and is required for osteoblast differentiation and bone formation."
* NP_001166938.1 transcription factor Sp7 isoform a.
* NP_690599.1 transcription factor Sp7 isoform a.
* XP_011536202.1 transcription factor Sp7 isoform X1.
* NP_001287766.1 transcription factor Sp7 isoform b.
GeneID: 221833 is SP8 Sp8 transcription factor. "The protein encoded by this gene is an SP family transcription factor that in mouse has been shown to be essential for proper limb development. Two transcript variants encoding different isoforms have been found for this gene."
* NP_874359.2 transcription factor Sp8 isoform 1.
* NP_945194.1 transcription factor Sp8 isoform 2.
GeneID: 100131390 is SP9 Sp9 transcription factor.

## Sp/KLF family

The Sp/KLF family (specificity protein/Krüppel-like factor) is a family of transcription factors, including the Kruppel-like factors as well as Sp1 transcription factor, Sp2 transcription factor, Sp3 transcription factor, Sp4 transcription factor, Sp8 transcription factor, Sp9; and possibly Sp5 and Sp7 transcription factor. KLF14 is also designated Sp6.