Homeobox expressed in ES cells 1, also known as homeobox protein ANF, is a
homeobox
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- ...
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
that in humans is encoded by the ''HESX1''
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
.
Expression of
HEX1 and HESX1 marks the
anterior visceral endoderm
In amniote embryology, the hypoblast, is one of two distinct layers arising from the inner cell mass in the mammalian blastocyst, or from the blastodisc in reptiles and birds. The hypoblast gives rise to the yolk sac, which in turn gives rise to ...
of the embryo. The AVE is an extra-embryonic tissue, key to the establishment of the anterior-posterior body axis.
Clinical significance
Mutations in the HESX1 gene are associated with some cases of
septo-optic dysplasia
Septo-optic dysplasia (SOD), known also as de Morsier syndrome, is a rare congenital malformation syndrome that features a combination of the underdevelopment of the optic nerve, pituitary gland dysfunction, and absence of the septum pellucidum (a ...
or
Pickardt-Fahlbusch syndrome.
References
Further reading
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External links
GeneReviews/NCBI/NIH/UW entry on Anophthalmia / Microphthalmia Overview*
Transcription factors
{{gene-3-stub