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KIAA1257 is a protein that in humans is encoded by the KIAA1257 gene. KIAA1257 has been shown to be involve with activation of genes involved in sex determination[3] .[4]

External IDsHomoloGene: 131623 GeneCards: KIAA1257
Gene location (Human)
Chromosome 3 (human)
Chr.Chromosome 3 (human)[1]
Chromosome 3 (human)
Genomic location for KIAA1257
Genomic location for KIAA1257
Band3q21.3Start128,909,866 bp[1]
End129,002,690 bp[1]
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC)Chr 3: 128.91 – 129 Mbn/a
PubMed search[2]n/a
View/Edit Human



In humans the gene KIAA1257 is located on chromosome 3q21.3. It spans 122 kilobasepairs (kBp) and contains 22 exons. It is flanked by Ras-related protein Rab-43 and several pseudogenes and on the opposite strand Acyl CoA dehydrogenase family member 9 (ACAD9) and EF-hand and coiled-coil domain containing 1 (EFCC1).

KIAA1257 genetic locus


The exons of KIAA1257 are alternatively spliced into 17 different isoforms (Table 1). Isoform X1 encodes the longest protein product and isoform X4 is the most common variant translated. Both the 5' and 3' UTR's are capable of forming stem loop structures that could serve as binding site for RNA-binding proteins.[5]

Isoform Length (bp)
X1 8645
X2 8641
X3 8218
X4 8612
X5 8370
X6 8190
X7 3524
X8 3428
X9 7801
X10 7685
X11 7862
X12 7809
X13 13296
X14 13401
X15 7579
X16 7585
X17 2163

Table 1


The protein KIAA1257 exists most commonly as a translation of the mRNA isoform X4, which is only half the length of isoform X1's product even though they have similar mRNA lengths. Protein isoform X1 is 1179 amino acids long, has a molecular weight of 136.4 kilodaltons (kDa) and an isoelectric point (pI) of 8.1.[6][7] KIAA1257 contains a domain of unknown function (DUF) 4550 in the first third of the protein sequence that has a high lysine content (15%).[6] Most of the protein exists in a random coil structure but the final thirds contains 6 predicted alpha helices.[8] KIAA1257 is predicted to be localized to the nucleus and contains several nuclear localization signals.[9] A summary of KIAA1257 orthologs is shown below.

Species Identity[10] Length[6] MW[6] pI[7] Localization (confidence)[9]
Human 100% 1179 136.4 8.1 Nucleus (73.9%)
Chimp 97% 1147 131.7 8.5 Nucleus (65.2%)
Dog 69% 1163 133.6 8.9 Nucleus (82.6%)
Turkey 39% 1174 132.0 8.5 Nucleus (65.2%)
Spotted gar 36% 1320 148.2 7.7 Nucleus (73.9%)

Table 2

Expression and RegulationEdit

KIAA1257 is mainly expressed in the testes and ovaries of adult humans, however expression is low in these tissues. KIAA1257 is most highly expressed during the earliest stages of development. Expression is the highest in the 2 through 8 cell stages of embryonic development and begins to decline steadily after morula and then blastocyst formation.[11]

KIAA1257 has a promoter region upstream of the 5' UTR with several transcription factor binding sites including a Sox11 binding site.[12] Sox11 is involved in the regulation of many developmental genes.

Clinical SignificanceEdit

KIAA1257 has been shown to activate expression of Nuclear receptor subfamily 5 group A member 1 (NR5A1).[3] NR5A1 is involved in sex determination and defects in the gene are related to XY sex reversal.


KIAA1257 is found in all vertebrates except for cartilaginous and jawless fishes. KIAA1257 orthologs in birds, fish, and reptiles have 30-40% identity with humans while mammals such as goats, cats, and dogs have 60-70% identity and primates have 85-99% identity.[13]

Species Identity Cover Length
Human 100% 100% 1179
Chimp 97% 99% 1147
Dog 69% 92% 1163
Prairie deer mouse 67% 93% 1164
Goat 61% 75% 931
Common shrew 58% 53% 660
Brown spotted pit viper 36% 77% 1080
Nile tilapia 34% 84% 1050

Table 3


  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000114656 - Ensembl, May 2017
  2. ^ "Human PubMed Reference:".
  3. ^ a b Noriko Sakai et al., Identification of NR5A1 (SF-1/AD4BP) gene expression modulators by large-scale gain and loss of function studies. J Endocrinol 198 (3) 489-497, doi: 10.1677/JOE-08-0027 First published online 25 June 2008
  4. ^ "Entrez Gene: KIAA1257". Retrieved 2017-03-02.
  5. ^ M. Zuker, D. H. Mathews & D. H. Turner. Algorithms and Thermodynamics for RNA Secondary Structure Prediction: A Practical Guide In RNA Biochemistry and Biotechnology, 11-43, J. Barciszewski and B. F. C. Clark, eds., NATO ASI Series, Kluwer Academic Publishers, Dordrecht, NL, (1999)
  6. ^ a b c d Algorithm Citation: Brendel, V., Bucher, P., Nourbakhsh, I.R., Blaisdell, B.E. & Karlin, S. (1992) "Methods and algorithms for statistical analysis of protein sequences" Proc. Natl. Acad. Sci. U.S.A. 89, 2002-2006. Program Citation: Volker Brendel, Department of Mathematics, Stanford University, Stanford CA 94305, U.S.A., modified; any errors are due to the modification.
  7. ^ a b Program by Dr. Luca Toldo, developed at Changed by Bjoern Kindler to print also the lowest found net charge. Available at EMBL WWW Gateway to Isoelectric Point Service {{cite web |url= |title=Archived copy |accessdate=2014-05-10 |deadurl=yes |archiveurl= |archivedate=2008-10-26 |df= }}
  8. ^ A. W. Burgess and P. K. Ponnuswamy and H. A. Sheraga, Analysis of conformations of amino acid residues and prediction of backbone topography in proteins, Israel J. Chem., p239-286, 1974, vol12.
  9. ^ a b Psort II
  10. ^ Altschul, S.F., Gish, W., Miller, W., Myers, E.W. & Lipman, D.J. (1990) "Basic local alignment search tool." J. Mol. Biol. 215:403-410
  11. ^ NCBI geo profiles GDS3959 / 1554852_a_at
  12. ^ "KIAA1257 promoter analysis".
  13. ^ Algorithm citation: E. W. Myers and W. Miller, (1989) CABIOS 4:11-17. W.R. Pearson & D.J. Lipman PNAS (1988) 85:2444-2448. W. R. Pearson (1990) "Rapid and Sensitive Sequence Comparison with FASTP and FASTA" Methods in Enzymology 183:63-98). Program citation: © 1997 by William R. Pearson and the University of Virginia (This is from distribution "fasta20u66", version 2.0u66, Sep., 1998, sale or incorporation into a commercial product expressly forbidden without permission).

Further readingEdit

  • Sakai N, Terami H, Suzuki S, Haga M, Nomoto K, Tsuchida N, Morohashi K, Saito N, Asada M, Hashimoto M, Harada D, Asahara H, Ishikawa T, Shimada F, Sakurada K (2008). "Identification of NR5A1 (SF-1/AD4BP) gene expression modulators by large-scale gain and loss of function studies". J. Endocrinol. 198 (3): 489–97. doi:10.1677/JOE-08-0027. PMID 18579725.