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 (genetics), transcription of genetics, genetic information from DNA to messenger RNA, by binding t ...
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, re ...
which bind to DNA to regulate the expression of genes. In particular this family of proteins can regulate the
Hox genes. They are regulators of
embryonic development
In developmental biology, animal embryonic development, also known as animal embryogenesis, is the developmental stage of an animal embryo. Embryonic development starts with the fertilization of an egg cell (ovum) by a sperm, sperm cell (spermat ...
and
hematopoiesis
Haematopoiesis (; ; also hematopoiesis in American English, sometimes h(a)emopoiesis) is the formation of blood cellular components. All cellular blood components are derived from haematopoietic stem cells. In a healthy adult human, roughly ten ...
in vertebrates, and are also involved in the development of some types of
gastrointestinal cancers and
leukemias.
Cdx proteins
Humans have three genes (
CDX1
Homeobox protein CDX-1 is a protein in humans that is encoded by the ''CDX1'' gene. CDX-1 is expressed in the developing endoderm and its expression persists in the intestine throughout adulthood. CDX-1 protein expression varies along the intesti ...
,
CDX2, and
CDX4) that encode the caudal proteins:
*
Cdx1 protein
*
Cdx2 protein
*Cdx4 protein
The
human
Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing ...
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 Cdx3.
Cdx proteins and regulation of Hox gene expression
Cdx proteins are key regulators of
Hox genes. The vertebrate Cdx proteins act
upstream of Hox genes. Cdx genes integrate the posteriorizing
signals from
retinoic acid and
Wnt canonical pathways and relay this information to Hox
promoters.
Expression in mouse embryo
Cdx2 expression begins at 3.5 days and is confined to the
trophectoderm, 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 folds 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 (genetics), transcription of genetics, genetic information from DNA to messenger RNA, by binding t ...
References
{{reflist
Transcription factors
Protein families