Paired related homeobox 1 is a protein that in humans is encoded by the PRRX1 gene. [5] [6]
The DNA-associated protein encoded by this gene is a member of the paired family of homeobox proteins localized to the nucleus. The protein functions as a transcription coactivator, enhancing the DNA-binding activity of serum response factor, a protein required for the induction of genes by growth and differentiation factors. The protein regulates muscle creatine kinase, indicating a role in the establishment of diverse mesodermal muscle types. Alternative splicing yields two isoforms that differ in abundance and expression patterns. [6]
Prrx1 expression is restricted to the mesoderm during embryonic development, and both Prrx1 and Prrx2 are expressed in mesenchymal tissues in adult mice. [7] [8] [9] [10] [11] Mice that lack both Prrx1 and Prrx2 have profound defects in mesenchymal cell differentiation in the craniofacial region. [9] [12] Several recent studies demonstrate that PRRX1 can regulate differentiation of mesenchymal precursors. For example, PRRX1 inhibits adipogenesis by activating transforming growth factor-beta (TGF-beta) signaling, [13] and also acts downstream of tumor necrosis factor-alpha to inhibit osteoblast differentiation. [14]
A homeobox is a DNA sequence, around 180 base pairs long, found within genes that are involved in the regulation of patterns of anatomical development (morphogenesis) in animals, fungi, plants, and numerous single cell eukaryotes. Homeobox genes encode homeodomain protein products that are transcription factors sharing a characteristic protein fold structure that binds DNA to regulate expression of target genes. Homeodomain proteins regulate gene expression and cell differentiation during early embryonic development, thus mutations in homeobox genes can cause developmental disorders.
Homeobox protein MSX-1, is a protein that in humans is encoded by the MSX1 gene. MSX1 transcripts are not only found in thyrotrope-derived TSH cells, but also in the TtT97 thyrotropic tumor, which is a well differentiated hyperplastic tissue that produces both TSHß- and a-subunits and is responsive to thyroid hormone. MSX1 is also expressed in highly differentiated pituitary cells which until recently was thought to be expressed exclusively during embryogenesis. There is a highly conserved structural organization of the members of the MSX family of genes and their abundant expression at sites of inductive cell–cell interactions in the embryo suggest that they have a pivotal role during early development.
Homeobox protein Hox-B7 is a protein that in humans is encoded by the HOXB7 gene.
Homeobox protein Hox-A10 is a protein that in humans is encoded by the HOXA10 gene.
Homeobox protein MSX-2 is a protein that in humans is encoded by the MSX2 gene.
Zinc finger E-box-binding homeobox 1 is a protein that in humans is encoded by the ZEB1 gene.
Homeobox protein Hox-A5 is a protein that in humans is encoded by the HOXA5 gene.
Hematopoietically-expressed homeobox protein HHEX is a protein that in humans is encoded by the HHEX gene and also known as Proline Rich Homeodomain protein PRH.
Prospero homeobox protein 1 is a protein that in humans is encoded by the PROX1 gene. The Prox1 gene is critical for the development of multiple tissues. Prox1 activity is necessary and sufficient to specify a lymphatic endothelial cell fate in endothelial progenitors located in the embryonic veins.
Homeobox protein Hox-A7 is a protein that in humans is encoded by the HOXA7 gene.
Homeobox protein DLX-3 is a protein that in humans is encoded by the DLX3 gene.
Homeobox protein DLX-4 is a protein that in humans is encoded by the DLX4 gene.
Homeobox protein Hox-A3 is a protein that in humans is encoded by the HOXA3 gene.
Visual system homeobox 1 is a protein that in humans is encoded by the VSX1 gene.
Homeobox protein DLX-2 is a protein that in humans is encoded by the DLX2 gene.
Homeobox protein Nkx-2.3 is a protein that in humans is encoded by the NKX2-3 gene.
Paired mesoderm homeobox protein 2 is a protein that in humans is encoded by the PRRX2 gene.
Homeobox protein SIX2 is a protein that in humans is encoded by the SIX2 gene.
Homeobox protein Nkx-6.1 is a protein that in humans is encoded by the NKX6-1 gene.
PBX/Knotted 1 Homeobox 2 (PKNOX2) protein belongs to the three amino acid loop extension (TALE) class of homeodomain proteins, and is encoded by PKNOX2 gene in humans. The protein regulates the transcription of other genes and affects anatomical development.
This article incorporates text from the United States National Library of Medicine, which is in the public domain.