Pax genes
Encyclopedia
Paired box gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

s
are a family of tissue specific transcription factors containing a paired domain and usually a partial or complete homeodomain. An octapeptide may also be present. Pax protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

s are important in early animal development for the specification of specific tissues, as well as during epimorphic limb regeneration in animals capable of such.

Groups

Within the mammalian family, there are four well defined groups of Pax genes.
  • Pax group 1 (Pax 1 and 9),
  • Pax group 2 (Pax 2, 5 and 8),
  • Pax group 3 (Pax 3 and 7) and
  • Pax group 4 (Pax 4 and 6).


Orthologous genes exist throughout the Metazoa, including extensive study of the ectopic expression
Ectopic expression
Ectopic expression is the expression of a gene in an abnormal place in an organism. This can be caused by a disease, or it can be artificially produced as a way to help determine what the function of that gene is....

 in Drosophila using murine Pax6.

Members

  • PAX1
    PAX1
    Paired box protein Pax-1 is a protein that in humans is encoded by the PAX1 gene.-Interactions:PAX1 has been shown to interact with MEOX1 and MEOX2....

     has been identified in mice with the development of vertebrate and embryo segmentation, and some evidence this is also true in humans. It transcribes a 440 amino acid
    Amino acid
    Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...

     protein from 4 exon
    Exon
    An exon is a nucleic acid sequence that is represented in the mature form of an RNA molecule either after portions of a precursor RNA have been removed by cis-splicing or when two or more precursor RNA molecules have been ligated by trans-splicing. The mature RNA molecule can be a messenger RNA...

    s and 1,323bps in humans.

  • PAX2
    PAX2
    Paired box gene 2, also known as PAX2 is a protein which in humans is encoded by the PAX2 gene.-Function: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...

     has been identified with kidney
    Kidney
    The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...

     and optic nerve development. It transcribes a 417 amino acid protein from 11 exons and 4,261 bps in humans. Mutation of PAX2 in humans has been associated with renal-coloboma syndrome as well as oligomeganephronia.

  • PAX3
    PAX3
    PAX3 is a gene that belongs to the paired box family of transcription factors. This gene was formerly known as splotch. PAX3 has been identified with ear, eye and facial development. Mutations in it can cause Waardenburg syndrome types 1 and 3...

     has been identified with ear, eye and facial development. It transcribes a 479 amino acid protein in humans. Mutations in it can cause Waardenburg syndrome
    Waardenburg syndrome
    Waardenburg syndrome Waardenburg syndrome Waardenburg syndrome (also Waardenburg­ Shah Syndrome, Waardenburg-Klein syndrome, Mende's syndrome II, Van der Hoeve-Halbertsma-Waardenburg syndrome, Ptosis-Epicanthus syndrome, Van der Hoeve-Halbertsma-Gualdi syndrome, Waardenburg type Pierpont,[5] Van...

    . PAX3
    PAX3
    PAX3 is a gene that belongs to the paired box family of transcription factors. This gene was formerly known as splotch. PAX3 has been identified with ear, eye and facial development. Mutations in it can cause Waardenburg syndrome types 1 and 3...

     is frequently expressed in melanomas
    Melanoma
    Melanoma is a malignant tumor of melanocytes. Melanocytes are cells that produce the dark pigment, melanin, which is responsible for the color of skin. They predominantly occur in skin, but are also found in other parts of the body, including the bowel and the eye...

     and contributes to tumor cell survival.

  • PAX4
    PAX4
    Paired box gene 4, also known as PAX4, is a protein which in humans is encoded by the PAX4 gene.- Function :This gene is a member of the paired box family of transcription factors. Members of this gene family typically contain a paired box domain, an octapeptide, and a paired-type homeodomain...

     has been identified with pancreatic islet beta cells. It transcribes a 350 amino acid protein from 9 exons and 2,010 bps in humans.

  • PAX5
    PAX5
    Paired box protein Pax-5 is a protein that in humans is encoded by the PAX5 gene.-Interactions:PAX5 has been shown to interact with TLE4 and Death associated protein 6.-Further reading:...

     has been identified with neural and spermatogenesis development and b-cell differentiation. It transcribes a 391 amino acid protein from 10 exons and 3,644bps in humans.

  • PAX6
    PAX6
    Paired box protein Pax-6 also known as aniridia type II protein or oculorhombin is a protein that in humans is encoded by the PAX6 gene.- Function :PAX6 is a member of the Pax gene family...

     is the most researched and appears throughout the literature as a "master control" gene for the development of eyes and sensory organs, certain neural and epidermal tissues as well as other homologous
    Homology (biology)
    Homology forms the basis of organization for comparative biology. In 1843, Richard Owen defined homology as "the same organ in different animals under every variety of form and function". Organs as different as a bat's wing, a seal's flipper, a cat's paw and a human hand have a common underlying...

     structures, usually derived from ectoderm
    Ectoderm
    The "ectoderm" is one of the three primary germ cell layers in the very early embryo. The other two layers are the mesoderm and endoderm , with the ectoderm as the most exterior layer...

    al tissues.

  • PAX7
    PAX7
    Paired box protein Pax-7 is a protein that in humans is encoded by the PAX7 gene.- Function :Pax-7 plays a role in neural crest development and gastrulation, and it is an important factor in the expression of neural crest markers such as Slug, Sox9, Sox10 and HNK-1....

     has been possibly associated with myogenesis
    Myogenesis
    Myogenesis is the formation of muscular tissue, in particular during embryonic development.Muscle fibers form from the fusion of myoblasts into multi-nucleated fibers . In the early development of an embryo these myoblasts will proliferate if enough fibroblast growth factor is present...

    . It transcribes a protein of 520 amino acids from 8 exons and 2,260bps in humans. PAX7 is required for the developmental specification of satellite cells in skeletal muscle
    Skeletal muscle
    Skeletal muscle is a form of striated muscle tissue existing under control of the somatic nervous system- i.e. it is voluntarily controlled. It is one of three major muscle types, the others being cardiac and smooth muscle...

    .

  • PAX8
    PAX8
    Paired box gene 8, also known as PAX8, is a protein which in humans is encoded by the PAX8 gene.- Function :This gene is a member of the paired box family of transcription factors. Members of this gene family typically encode proteins which contain a paired box domain, an octapeptide, and a...

     has been associated with thyroid
    Thyroid
    The thyroid gland or simply, the thyroid , in vertebrate anatomy, is one of the largest endocrine glands. The thyroid gland is found in the neck, below the thyroid cartilage...

     specific expression. It transcribes a protein of 451 amino acids from 11 exons and 2,526bps in humans.

  • PAX9
    PAX9
    Paired box gene 9, also known as PAX9, is a protein which in humans is encoded by the PAX9 gene. It is also found in mammals generally.- Function :This gene is a member of the paired box family of transcription factors...

     has found to be associated with a number of organ and other skeletal developments, particularly teeth. It transcribes a protein of 341 amino acids from 4 exons and 1,644bps in humans.

External links

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