Homeobox protein CDX-1 is a
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 ...
in humans that is encoded by the ''CDX1''
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 ...
.
CDX1 is expressed in the developing
endoderm
Endoderm is the innermost of the three primary germ layers in the very early embryo. The other two layers are the ectoderm (outside layer) and mesoderm (middle layer). Cells migrating inward along the archenteron form the inner layer of the gast ...
and its expression persists in the intestine throughout adulthood.
CDX1 protein expression varies along the intestine, with high expression in intestinal crypts and diminishing expression along intestinal villi.
Function
This gene is a member of the
caudal-related
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- ...
transcription factor
In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence. The fu ...
family. The encoded DNA-binding protein regulates intestine-specific gene expression and enterocyte differentiation. It has been shown to induce expression of the intestinal alkaline phosphatase gene, and inhibit beta-catenin/T-cell factor transcriptional activity.
CDX1 has also been shown to play an important role in embryonic epicardial development. It has been demonstrated that CDX proteins suppress cardiac differentiation in both zebrafish and mouse embryonic stem cells, but the overall mechanism for how this happens is poorly understood.
However, CDX1 has been shown to be transiently expressed in the embryonic heart 11.5 days post coitum (dpc). This transient expression is thought to induce epicardial epithelial-to-mesynchemal transition and thus proper cardiovascular formation. It has been shown that low-dose CDX1 induction caused enhanced migration and differentiation of epicardium-derived cells into vascular smooth muscle, where as continued high dose induction of CDX1 or CDX1 deficiency diminished the ability of these cells to migrate and differentiate into smooth muscle by the actions of TGF-β1. Furthermore, CDX1 induction also altered transcript expression of genes related to cell adhesions for EMT and angiogenesis.
Therefore, along with its known roles in intestinal patterning and differentiation, CDX1 is also shown to be important in epicardial development.
References
Further reading
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External links
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Transcription factors
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