Iroquois-class homeodomain protein IRX-3, also known as Iroquois homeobox protein 3, is a protein that in humans is encoded by the IRX3 gene. [5]
Iroquois-class homeodomain protein IRX-3, also known as Iroquois homeobox protein 3, is a protein that in humans is encoded by the IRX3 gene. [5]
The Iroquois family of genes was discovered in Drosophila during a mutagenesis experiment designed to identify genes that affected the development of external sensory organs. When genes of this family were knocked out, the Drosophila flies expressed a unique patterning of bristles reminiscent of Iroquois American Indians, they were subsequently named after them. [6] The molecular characteristics of these genes allowed the identification of homologs in C. elegans and several other vertebrates. [7]
IRX3 is a member of the Iroquois homeobox gene family and plays a role in an early step of neural development. [8] Members of this family appear to play multiple roles during pattern formation of vertebrate embryos. [5] [9] Specifically, IRX3 contributes to pattern formation in the spinal cord where it translates a morphogen gradient into transcriptional events, and is directly regulated by NKX2-2. [10] The Irx3 gene controls the subdivision of the neural territory by working together with various other homeodomain factors, all of these factors are expressed in partially overlapping domains along the dorsoventral axis in response to Sonic hedgehog molecules emanating from the floor plate. The combination of these signals defines five regions, each of which will give rise to five types of neurons (V0, V1, V2, MN, and V3). For example, the region that generates V2 neurons expresses both Irx3 and Nkx6.1, while that which forms MN neurons expresses Nkx6.1 alone. Irx3 overexpression in the MN domain transforms MN into V2 neurons. [11]
Obesity-associated noncoding sequences within FTO interact with the promoter of IRX3 and FTO in human, mouse, and zebrafish. Obesity-associated single nucleotide polymorphisms are related to the expression of IRX3 (not FTO) in the human brain. A direct connection between the expression of IRX3 and body mass and composition was shown through the decrease in body weight of 25-30% in IRX3-deficient mice. This suggests that IRX3 influences obesity. [12] Manipulation of IRX3 and IRX5 pathways has also been shown to decrease obesity markers in human cell cultures. [13] Genetic variants of FTO and IRX3 genes are in high linkage disequilibrium and are associated with obesity risk. [14]
A homeobox is a DNA sequence, around 180 base pairs long, that regulates large-scale anatomical features in the early stages of embryonic development. For instance, mutations in a homeobox may change large-scale anatomical features of the full-grown organism.
Sonic hedgehog protein(SHH) is encoded for by the SHH gene. The protein is named after the character Sonic the Hedgehog.
Fat mass and obesity-associated protein also known as alpha-ketoglutarate-dependent dioxygenase FTO is an enzyme that in humans is encoded by the FTO gene located on chromosome 16. As one homolog in the AlkB family proteins, it is the first mRNA demethylase that has been identified. Certain alleles of the FTO gene appear to be correlated with obesity in humans.
Homeobox protein Nkx-3.1, also known as NKX3-1, NKX3, BAPX2, NKX3A and NKX3.1 is a protein that in humans is encoded by the NKX3-1 gene located on chromosome 8p. NKX3-1 is a prostatic tumor suppressor gene.
Homeobox protein Nkx-2.5 is a protein that in humans is encoded by the NKX2-5 gene.
LIM/homeobox protein Lhx3 is a protein that in humans is encoded by the LHX3 gene.
Homeobox protein Emx2 is a protein that in humans is encoded by the EMX2 gene.
Homeobox protein Nkx-2.2 is a protein that in humans is encoded by the NKX2-2 gene.
Pituitary homeobox 3 is a protein that in humans is encoded by the PITX3 gene.
Homeobox protein DLX-1 is a protein that in humans is encoded by the DLX1 gene.
Homeobox protein Nkx-2.3 is a protein that in humans is encoded by the NKX2-3 gene.
NK3 homeobox 2 also known as NKX3-2 is a human gene. It is a homolog of bagpipe (bap) in Drosophila and therefore also known as Bapx1. The protein encoded by this gene is a homeodomain containing transcription factor.
Homeobox protein Nkx-6.1 is a protein that in humans is encoded by the NKX6-1 gene.
Iroquois homeobox factors are a family of homeodomain transcription factors that play a role in many developmental processes. The loci were named for the flies carrying mutations in one of these genes, which are devoid of all bristles in the lateral part of the notum, leaving only a median stripe of bristles, similar to the Iroquois tribes which shaved all but a medial stripe of hairs on the head.
Iroquois-class homeodomain protein IRX-1, also known as Iroquois homeobox protein 1, is a protein that in humans is encoded by the IRX1 gene. All members of the Iroquois (IRO) family of proteins share two highly conserved features, encoding both a homeodomain and a characteristic IRO sequence motif. Members of this family are known to play numerous roles in early embryo patterning. IRX1 has also been shown to act as a tumor suppressor gene in several forms of cancer.
Iroquois-class homeodomain protein IRX-2, also known as Iroquois homeobox protein 2, is a protein that in humans is encoded by the IRX2 gene.
Iroquois-class homeodomain protein IRX-4, also known as Iroquois homeobox protein 4, is a protein that in humans is encoded by the IRX4 gene.
Iroquois-class homeodomain protein IRX-5, also known as Iroquois homeobox protein 5, is a protein that in humans is encoded by the IRX5 gene.
Iroquois-class homeodomain protein IRX-6, also known as Iroquois homeobox protein 6, is a protein that in humans is encoded by the IRX6 gene.
The Gsx gene family are a group of genes found in many, but not all, animals. Gsx genes contain a homeobox DNA sequence and code for proteins that act as transcription factors. The human genome has two Gsx genes, called GSX1 and GSX2, while the fruitfly Drosophila has a single Gsx gene called ind. Vertebrate Gsx genes are implicated in neural patterning. In many animals, Gsx genes can be part of a ParaHox gene cluster.
This article incorporates text from the United States National Library of Medicine, which is in the public domain.
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