The Cdx protein family is a group of the
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 f ...
proteins
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 ...
which bind to DNA to regulate the expression of genes. In particular this family of proteins can regulate the
Hox genes
Hox genes, a subset of homeobox genes, are a group of related genes that specify regions of the body plan of an embryo along the head-tail axis of animals. Hox proteins encode and specify the characteristics of 'position', ensuring that the co ...
. They are regulators of
embryonic development
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm ...
and
hematopoiesis
Haematopoiesis (, from Greek , 'blood' and 'to make'; also hematopoiesis in American English; sometimes also h(a)emopoiesis) is the formation of blood cellular components. All cellular blood components are derived from haematopoietic stem cells ...
in vertebrates, and are also involved in the development of some types of
gastrointestinal cancer
Gastrointestinal cancer refers to malignant conditions of the gastrointestinal tract (GI tract) and accessory organs of digestion, including the esophagus, stomach, biliary system, pancreas, small intestine, large intestine, rectum and anus. Th ...
s and
leukemia
Leukemia ( also spelled leukaemia and pronounced ) is a group of blood cancers that usually begin in the bone marrow and result in high numbers of abnormal blood cells. These blood cells are not fully developed and are called ''blasts'' or ...
s.
Cdx proteins
Humans have three genes (
CDX1
Homeobox protein CDX-1 is a protein in humans that is encoded by the ''CDX1'' gene. CDX1 is expressed in the developing endoderm and its expression persists in the intestine throughout adulthood. CDX1 protein expression varies along the intestine, ...
,
CDX2, and
CDX4) that encode the caudal proteins:
*
Cdx1 protein
*
Cdx2 protein
*Cdx4 protein
The
human
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...
Cdx2 family protein has 94% identity with the
mouse
A mouse ( : mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...
Cdx2 and the
hamster
Hamsters are rodents (order Rodentia) belonging to the subfamily Cricetinae, which contains 19 species classified in seven genera.Fox, Sue. 2006. ''Hamsters''. T.F.H. Publications Inc. They have become established as popular small pets. The ...
Cdx3.
Cdx proteins and regulation of Hox gene expression
Cdx proteins are key regulators of
Hox genes
Hox genes, a subset of homeobox genes, are a group of related genes that specify regions of the body plan of an embryo along the head-tail axis of animals. Hox proteins encode and specify the characteristics of 'position', ensuring that the co ...
. The vertebrate Cdx proteins act
upstream
Upstream may refer to:
* Upstream (bioprocess)
* ''Upstream'' (film), a 1927 film by John Ford
* Upstream (networking)
* ''Upstream'' (newspaper), a newspaper covering the oil and gas industry
* Upstream (petroleum industry)
* Upstream (software ...
of Hox genes. Cdx genes integrate the posteriorizing
signals from
retinoic acid and
Wnt canonical pathways #REDIRECT WNT
{{redirect category shell, {{R from ambiguous page{{R from other capitalisation ...
and relay this information to Hox
promoters.
Expression in mouse embryo
Cdx2 expression begins at 3.5 days and is confined to the
trophectoderm
The trophoblast (from Greek : to feed; and : germinator) is the outer layer of cells of the blastocyst. Trophoblasts are present four days after fertilization in humans. They provide nutrients to the embryo and develop into a large part of the ...
, being absent from the inner cell mass. From 8.5 days, Cdx2 begins to be expressed in embryonic tissues, principally in the posterior part of the gut from its earliest formation.
See also
*
Neural tube
In the developing chordate (including vertebrates), the neural tube is the embryonic precursor to the central nervous system, which is made up of the brain and spinal cord. The neural groove gradually deepens as the neural fold become elevated, ...
*
Protein family
A protein family is a group of evolutionarily related proteins. In many cases, a protein family has a corresponding gene family, in which each gene encodes a corresponding protein with a 1:1 relationship. The term "protein family" should not be ...
*
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 f ...
References
{{reflist
Transcription factors
Protein families