NKX3-1
Available structures PDB Ortholog search:PDBeRCSB List of PDB id codes 2L9R
Identifiers
Aliases	NKX3-1, BAPX2, NKX3, NKX3.1, NKX3A, NK3 homeobox 1
External IDs	OMIM:602041;MGI:97352;HomoloGene:4494;GeneCards:NKX3-1;OMA:NKX3-1 - orthologs
Gene location (Human) Chr. Chromosome 8 (human)[1] Band 8p21.2 Start 23,678,697bp[1] End 23,682,938bp[1]
Gene location (Mouse) Chr. Chromosome 14 (mouse)[2] Band 14 D2|14 36.02 cM Start 69,428,087bp[2] End 69,432,111bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in palpebral conjunctiva secondary oocyte sperm prostate trachea germinal epithelium urethra testicle mucosa of nose minor salivary glands Top expressed in prostatic epithelium vasculature of trunk urethral gland (male) bulbo-urethral gland descending aorta renal artery dorsal aorta anterior lobe of prostate gastrula incisor More reference expression data BioGPS More reference expression data
Gene ontology Molecular function sequence-specific DNA binding DNA binding DNA-binding transcription factor activity transcription factor binding histone deacetylase binding transcription cis-regulatory region binding RNA polymerase II general transcription initiation factor activity estrogen receptor activity protein kinase activator activity protein self-association MADS box domain binding protein binding cysteine-type endopeptidase activator activity involved in apoptotic process estrogen receptor binding DNA-binding transcription factor activity, RNA polymerase II-specific RNA polymerase II cis-regulatory region sequence-specific DNA binding nuclear receptor activity Cellular component intracellular anatomical structure nucleus site of DNA damage Biological process somitogenesis androgen receptor signaling pathway cellular response to steroid hormone stimulus dorsal aorta development positive regulation of protein phosphorylation male gonad development positive regulation of cell death regulation of transcription, DNA-templated protein kinase B signaling response to testosterone epithelial cell proliferation involved in salivary gland morphogenesis cellular response to tumor necrosis factor positive regulation of androgen secretion positive regulation of mitotic cell cycle positive regulation of apoptotic signaling pathway prostate gland development negative regulation of gene expression transcription, DNA-templated multicellular organism development positive regulation of transcription, DNA-templated salivary gland development heart development positive regulation of cysteine-type endopeptidase activity involved in apoptotic process positive regulation of gene expression positive regulation of response to DNA damage stimulus branching involved in prostate gland morphogenesis negative regulation of epithelial cell proliferation involved in prostate gland development positive regulation of cell population proliferation cellular response to interleukin-1 negative regulation of epithelial cell proliferation negative regulation of insulin-like growth factor receptor signaling pathway urogenital system development positive regulation of phosphatidylinositol 3-kinase signaling metanephros development negative regulation of transcription, DNA-templated activation of cysteine-type endopeptidase activity involved in apoptotic process branching morphogenesis of an epithelial tube positive regulation of intrinsic apoptotic signaling pathway positive regulation of cell division cellular response to hypoxia positive regulation of transcription by RNA polymerase II negative regulation of cell population proliferation negative regulation of mitotic cell cycle pharyngeal system development activation of protein kinase activity regulation of protein localization positive regulation of DNA-binding transcription factor activity cell differentiation Sources:Amigo /QuickGO
Orthologs Species Human Mouse Entrez 4824 18095 Ensembl ENSG00000167034 ENSMUSG00000022061 UniProt Q99801 P97436 RefSeq (mRNA) NM_001256339 NM_006167 NM_010921 RefSeq (protein) NP_001243268 NP_006158 NP_035051 Location (UCSC) Chr 8: 23.68 – 23.68 Mb Chr 14: 69.43 – 69.43 Mb PubMed search [3] [4]
Wikidata
View/Edit Human View/Edit Mouse

Homeobox protein Nkx-3.1, also known as NKX3-1, NKX3, BAPX2, NKX3A and NKX3.1 is aprotein that in humans is encoded by theNKX3-1gene located on chromosome 8p.^[5]NKX3-1 is a prostatictumor suppressor gene.

NKX3-1 is anandrogen-regulated, prostate-specifichomeobox gene whose expression is predominantly localized to prostate epithelium. It acts as atranscription factor that has critical function in prostate development and tumor suppression. It is a negative regulator of epithelial cell growth in prostate tissue. The NKX3-1 homeoboxprotein is encoded by theNKX3-1gene.^[5]

The homeodomain-containing transcription factor NKX3A is a putative prostate tumor suppressor that is expressed in a largely prostate-specific and androgen-regulated manner. Loss of NKX3A protein expression is a common finding in human prostate carcinomas and prostatic intraepithelial neoplasia.^[6]

In humans, theNKX3-1 gene is located on chromosome 8p21.2 with 4 exons.^[7] The 8p chromosome is a region that is frequently reported to undergo aloss of heterozygosity (LOH) associated with tissue dedifferentiation and loss of androgen responsiveness during the progression ofprostate cancer. LOH has been reported to be observed in 12-89% of high-grade prostatic intraepithelial neoplasia (PIN) and 35-86% of prostatic adenocarcinomas. The frequency of loss of heterozygosity on chromosome 8p is seen to increase with advanced prostate cancer grade and stage.^[8]

NKX3-1 contains two exons encoding a 234 amino acid protein including a homeodomain. The 234 amino acids are 35-38 kDa. One N-terminal domain one homeodomain and one C-terminal domain are present. The observed interaction between NKX3-1 and Serum Response Factor (SRF)indicate that amino-terminal domains participate in the interaction. The synergistic transcriptional activation requires both interactions at multiple protein-protein interfaces and protein-DNA interactions. This indicates that one mechanism of NKX3-1 dependent transcriptional activation in prostate epithelia requires combinatorial interactions with other factors expressed within those cells^[9]

In 2000, full length NKX3-1 cDNA was obtained from a human prostate cDNA library. Korkmaz et al.^[10] identified 3 splice variants with deletions in the N-terminal region as well as a variant at position 137 within the homeobox domain. NKX3-1 expression was visualized using Fluorescence microscopy, utilizing GFP-NKX3-1 in the nucleus.

NKX3-1 expression acts as a transcription factor that has been found to play a main role in prostate development and tumor suppression. The loss of NKX3-1 expression is frequently observed in prostatetumorigenesis and has been seen to be a result of allelic loss, methylation, and post transcriptional silencing.^[11] NKX3-1 expression is seen in prostate epithelium, testis, ureter, and pulmonary bronchial mucous glands.

NKX3-1 binds to DNA to suppress transcription as well as interacts with transcription factors such as serum response factor, to enhance transcriptional activation. Wang et al.^[12] demonstrated that NKX3-1 marks a stem cell population that functions during prostate regeneration. Genetic lineage marking demonstrated that rare luminal cells that express NKX3-1 in the absence of testicular androgens are bipotential and can self-renew in vivo. Single-cell transplantation assays showed that castration-resistant NKX3-1 expressing cells (CARNs) can reconstitute prostate ducts in renal grafts. Functional assays of NKX3-1 mutant mice in serial prostate regeneration suggested that NKX3-1 is required for stem cell maintenance. Furthermore, targeted deletion of PTEN gene in CARNs resulted in rapid carcinoma formation after androgen-mediated regeneration. This indicates that CARNs represent a new luminal stem cell population that is an efficient target for oncogenic transformation in prostate cancer.

It has also been found to be essential inpluripotency ofstem cells usingYamanaka factors.^[13]

In 2010 it was shown that NKX3-1 was controlled by ERG and ESE3 both directly and through induction of EZH2 (Polycomb group pcg).^[14]

Using a random cDNA sequencing approach, He et al.^[15] cloned a novel prostate-specific gene that encoded a homeobox-containing protein. The gene which they symbolized NKX3-1 encoded a 234-amino acid polypeptide with greatest homology to the Drosophila NK3 gene. Northern blot analysis showed that NKX3.1 had a uniquely restricted tissue expression pattern with mRNA being abundant in the prostate, lower levels in the testis and absent from all other tissues tested. The NKX3-1 protein expression was detected a hormone-responsive, androgen receptor-positive prostate cancer cell line, but was absent from androgen receptor-negative prostate cancer cell lines as well as other cell lines of varied origins. The link between androgen stimulation and NKX3-1 was discovered through the use of an androgen-dependent carcinoma line. The researchers suggested that theNKX3-1 gene plays a role in androgen-driven differentiation of prostatic tissue as well as in loss of differentiation during the progression of prostate cancer.

Prostate cancer is the most commonly diagnosed cancer in American men and the second leading cause of cancer related deaths.^[16] Prostate cancer predominantly occurs in the peripheral zone of the human prostate, with fewer than 10% of cases found in the central zone. The disease develops as a result of the temporal and spatial loss of the basal epithelial compartment as well as increased proliferation and dedifferentiation of the luminal (secretory) epithelial cells. Prostate cancer is typically found in men of ages older than 60 and its incidence increases with increasing age.

NKX3-1 plays an essential role in normal murine prostate development. Loss of function ofNKX3-1 leads to defects in prostatic protein secretions as well as ductal morphogenesis. Loss of function also contributes to prostate carcinogenesis.

Furthermore,immunohistochemistry using anti-NKX3-1 antibodies provides a sensitive and specific method for diagnosing metastatic prostatic adenocarcinomas in distant sites.^[17]

NKX3-1 has been shown tointeract withSPDEF.^[18]

The stability of NKX3-1 protein has been shown to be regulated by phosphorylation.^[19]

• NKX3-1+protein,+human at the U.S. National Library of MedicineMedical Subject Headings (MeSH)

This article incorporates text from theUnited States National Library of Medicine, which is in thepublic domain.

• Genes on human chromosome 8
• Transcription factors

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