Biology:PAX2

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Short description: Protein-coding gene in humans


A representation of the 3D structure of the protein myoglobin showing turquoise α-helices.
Generic protein structure example

Paired box gene 2, also known as Pax-2, is a protein which in humans is encoded by the PAX2 gene.[1][2]

Function

The Pax Genes, or Paired-Box Containing Genes, play important roles in the development and proliferation of multiple cell lines, development of organs, and development and organization of the central nervous system.[3] The transcription factor gene PAX2 is important in the regionalized embryological development of the central nervous system. In mammals, the brain is developed in three regions: the forebrain, midbrain, and the hindbrain.[4] Concentration gradients of fibroblast growth factor 8 (FGF8) and Wingless-Type MMTV Integration Site Family, Member 1 (Wnt1) control expression of Pax-2 during development of the Mesencephalon, or midbrain.[5] Similar patterning during embryological development can be observed in “basal chordates or ascidians,” in which organization of the central nervous system in ascidian larvae are also controlled by fibroblast growth factor genes.[4] PAX2 encodes for the transcription factor which appears to be essential in the organization of the midbrain and hindbrain regions, and at the earliest can be detected on either side of the sulcus limitans, which separates motor and sensory nerve nuclei.[3][6]

PAX2 encodes paired box gene 2, one of many human homologues of the Drosophila melanogaster gene prd. The central feature of this transcription factor gene family is the conserved DNA-binding paired box domain. PAX2 is believed to be a target of transcriptional suppression by the tumor suppressor gene WT1. Pax 2 is a transcription factor controlled by the signaling molecules Wnt1 and Fgf8. Pax2 along with other transcription factors Pax5, Pax8, En1, and En 2 are expressed across the Otx2-Gbx2 boundary in the mid-hindbrain region. These transcription factors work with the signaling molecules Wnt1 and Fgf8 to maintain the MHB organizer. The MHB controls midbrain and cerebellum development. Pax2 is the earliest known gene to be expressed across the Otx2-Gbx2 boundary. It is first expressed in the late primitive streak stage and is expressed in a narrow ring centered at the MHB during somitogenesis. Transgene expression of the mid-hindbrain and developing kidney is directed by Pax2. There are three distinct MHB-specific enhancers in the upstream region of Pax2. Expression at the MHB from the four-somite stage onwards is directed by the two late enhancers in the proximal and distal regions of Pax2. The early enhancer located in the intermediate region activates the mid-hindbrain region of late gastrula embryos. The activation of Pax2, Pax5, and Pax8 is a conserved feature of all vertebrates.

Clinical significance

Pathologically, Pax2 has been demonstrated to activate hepatocyte growth factor (HGF) gene promoter, and both have been indicated as playing a role in human prostate cancers.[7]

Mutations within PAX2 have been shown to result in optic nerve colobomas and renal hypoplasia. Alternative splicing of this gene results in multiple transcript variants.[8] Pax2 and Pax8 are also necessary for the formation of the pronephros and subsequent kidney structures. Pax2 and Pax8 regulate the expression of Gata3. Without these genes mutations in the urogenital system arise.

Pax2 misexpression is frequently observed in proliferative disorders of the kidney. For example, Pax2 is highly expressed in polycystic kidney disease (PKD), Wilms' tumor (WT), and renal cell carcinoma (RCC).[9] Pax2 expression in these diseases appears fuel cell cycling, inhibit cell death, and confer resistance to chemotherapy.[9] Due to its role in these diseases, Pax2 is an attractive therapeutic target and a number of methods for inhibiting its activity have been investigated. In fact, a small-molecule was recently identified with the ability to disrupt Pax2 mediated transcription by blocking Pax2 from binding to DNA.[10][11]

Interactions

PAX2 has been shown to interact with PAXIP1.[12]

See also

References

  1. "Mapping of the human homologs of the murine paired-box-containing genes". Mammalian Genome 4 (2): 78–82. 1993. doi:10.1007/BF00290430. PMID 8431641. 
  2. "Chromosomal localization of seven PAX genes and cloning of a novel family member, PAX-9". Nature Genetics 3 (4): 292–8. Apr 1993. doi:10.1038/ng0493-292. PMID 7981748. 
  3. 3.0 3.1 "Pax Gene". Brenner's Encyclopedia of Genetics (2nd ed.). San Diego: Elsevier Science. 2013. pp. 246–248. doi:10.1016/B978-0-12-374984-0.01128-1. ISBN 978-0-08-096156-9. 
  4. 4.0 4.1 "Region specific gene expressions in the central nervous system of the ascidian embryo". Mechanisms of Development 119 (Suppl 1): S275–7. 2002. doi:10.1016/S0925-4773(03)00128-X. PMID 14516697. 
  5. GeneCard for WNT1
  6. Nolte, John (2009). The human brain: an introduction to its functional anatomy (6th ed.). Philadelphia, PA: Mosby/Elsevier. p. 685. ISBN 978-0-323-04131-7. 
  7. "PAX2 promoted prostate cancer cell invasion through transcriptional regulation of HGF in an in vitro model". Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease 1852 (11): 2467–73. 2015. doi:10.1016/j.bbadis.2015.08.008. PMID 26296757. 
  8. "Entrez Gene: PAX2 paired box gene 2". https://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=5076. 
  9. 9.0 9.1 "Pax genes in renal development, disease and regeneration". Seminars in Cell and Developmental Biology 44: 97–106. 2015. doi:10.1016/j.semcdb.2015.09.016. PMID 26410163. 
  10. "Inhibition of Pax2 Transcription Activation with a Small Molecule that Targets the DNA Binding Domain". ACS Chemical Biology 12 (3): 724–734. 2017. doi:10.1021/acschembio.6b00782. PMID 28094913. 
  11. "Are Pax proteins potential therapeutic targets in kidney disease and cancer?". Kidney International 94 (2): 259–267. 2018. doi:10.1016/j.kint.2018.01.025. PMID 29685496. 
  12. "PTIP, a novel BRCT domain-containing protein interacts with Pax2 and is associated with active chromatin". Nucleic Acids Research 28 (14): 2741–51. Jul 2000. doi:10.1093/nar/28.14.2741. PMID 10908331. 

Further reading

External links

This article incorporates text from the United States National Library of Medicine, which is in the public domain.