HOXA3

Homeobox protein Hox-A3 is a protein that in humans is encoded by the HOXA3 gene.^[5][6][7]

Function

In vertebrates, the genes encoding the class of transcription factors called homeobox genes are found in clusters named A, B, C, and D on four separate chromosomes. Expression of these proteins is spatially and temporally regulated during embryonic development. This gene is part of the A cluster on chromosome 7 and encodes a DNA-binding transcription factor which may regulate gene expression, morphogenesis, and differentiation. Three transcript variants encoding two different isoforms have been found for this gene.^[7]

During normal fetal development, HoxA3 is expressed in mesenchymal neural crest cells and endodermal cells found in the third pharyngeal pouch.^[8] Expression of HoxA3 in these cells affects the proper formation of the thymus, thyroid, and parathyroid organs.^[9][10] While the gene does not seem to affect the proliferation or migration of the pharyngeal neural crest cells, it does appear to trigger cellular differentiation events required to form these organs.^[9] Knockout of HoxA3 leads to failure in forming the thymus (athymia) and parathyroid gland (aparthyroidism).^[10] Mutant HoxA3 also causes a reduction in thyroid size. While the follicular and parafollicular cells still differentiate, their numbers are reduced and they are not evenly distributed throughout the gland.^[9] Mutant HoxA3 models show similar phenotypes as those seen in DiGeorge’s Syndrome, and it is possible that the two are linked.^[9]

Regulation

The HOXA3 gene is

• Homeobox

References

Further reading

• Apiou F, Flagiello D, Cillo C, Malfoy B, Poupon MF, Dutrillaux B (1996). "Fine mapping of human HOX gene clusters". Cytogenetics and Cell Genetics. 73 (1–2): 114–5.
  PMID 8646877
  .
• Bonaldo MF, Lennon G, Soares MB (September 1996). "Normalization and subtraction: two approaches to facilitate gene discovery". Genome Research. 6 (9): 791–806.
  PMID 8889548
  .
• Manley NR, Capecchi MR (March 1998). "Hox group 3 paralogs regulate the development and migration of the thymus, thyroid, and parathyroid glands". Developmental Biology. 195 (1): 1–15.
  PMID 9520319
  .
• Sanger Centre, The; Washington University Genome Sequencing Cente, The (November 1998). "Toward a complete human genome sequence". Genome Research. 8 (11): 1097–108.
  PMID 9847074
  .
• Mulder GB, Manley N, Maggio-Price L (December 1998). "Retinoic acid-induced thymic abnormalities in the mouse are associated with altered pharyngeal morphology, thymocyte maturation defects, and altered expression of Hoxa3 and Pax1". Teratology. 58 (6): 263–75.
  PMID 9894676
  .
• Manzanares M, Nardelli J, Gilardi-Hebenstreit P, Marshall H, Giudicelli F, Martínez-Pastor MT, Krumlauf R, Charnay P (February 2002). "Krox20 and kreisler co-operate in the transcriptional control of segmental expression of Hoxb3 in the developing hindbrain". The EMBO Journal. 21 (3): 365–76.
  PMID 11823429
  .
• Kosaki K, Kosaki R, Suzuki T, Yoshihashi H, Takahashi T, Sasaki K, Tomita M, McGinnis W, Matsuo N (February 2002). "Complete mutation analysis panel of the 39 human HOX genes". Teratology. 65 (2): 50–62.
  PMID 11857506
  .
• Kim J, Bhinge AA, Morgan XC, Iyer VR (January 2005). "Mapping DNA-protein interactions in large genomes by sequence tag analysis of genomic enrichment". Nature Methods. 2 (1): 47–53.
  S2CID 6135437
  .
• Wissmüller S, Kosian T, Wolf M, Finzsch M, Wegner M (2006). "The high-mobility-group domain of Sox proteins interacts with DNA-binding domains of many transcription factors". Nucleic Acids Research. 34 (6): 1735–44.
  PMID 16582099
  .

External links

• HOXA3+protein,+human at the U.S. National Library of Medicine Medical Subject Headings (MeSH)

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

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