TYMP is a gene that encodes for the enzyme
thymidine phosphorylase
Thymidine phosphorylase () is an enzyme that is encoded by the TYMP (gene), TYMP gene and catalyzes the reaction:
:thymidine + phosphate \rightleftharpoons thymine + 2-deoxy-alpha-D-ribose 1-phosphate
Thymidine phosphorylase is involved in purin ...
.
The ''TYMP'' gene is also known as ECGF1 (endothelial cell growth factor 1, platelet-derived) and MNGIE due to its role in
MNGIE syndrome.
Structure
The ''TYMP'' gene is located on chromosome 22 in humans and contains 10 exons spanning more than 4.3 kb.
Function
''TYMP'' encodes for the enzyme
thymidine phosphorylase
Thymidine phosphorylase () is an enzyme that is encoded by the TYMP (gene), TYMP gene and catalyzes the reaction:
:thymidine + phosphate \rightleftharpoons thymine + 2-deoxy-alpha-D-ribose 1-phosphate
Thymidine phosphorylase is involved in purin ...
. ''TYMP'' and thymidine phosphorylase are associated with
angiogenesis
Angiogenesis is the physiological process through which new blood vessels form from pre-existing vessels, formed in the earlier stage of vasculogenesis. Angiogenesis continues the growth of the vasculature by processes of sprouting and splitting ...
, growth of
endothelial cell
The endothelium is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the rest of the vessel ...
s, and
mitochondrial neurogastrointestinal encephalomyopathy (MNGIE).
Thymidine phosphorylase is angiogenic
growth factor
A growth factor is a naturally occurring substance capable of stimulating cell proliferation, wound healing, and occasionally cellular differentiation. Usually it is a secreted protein or a steroid hormone. Growth factors are important for regu ...
which promotes
angiogenesis
Angiogenesis is the physiological process through which new blood vessels form from pre-existing vessels, formed in the earlier stage of vasculogenesis. Angiogenesis continues the growth of the vasculature by processes of sprouting and splitting ...
in vivo and stimulates the in vitro growth of a variety of endothelial cells. Thymidine phosphorylase has a highly restricted target cell specificity acting only on
endothelial cell
The endothelium is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the rest of the vessel ...
s, hence its alternative name of ECGF1. Because it limits glial cell proliferation, thymidine phosphorylase is also known as gliostatin. Thymidine phosphorylase activity in leukocytes from
mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) patients was less than 5 percent of controls, indicating that loss-of-function mutations in ''TYMP'' cause MNGIE.
Interactive pathway map
References
Further reading
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External links
GeneReviews/NIH/NCBI/UW entry on Mitochondrial Neurogastrointestinal Encephalopathy Disease (MNGIE)
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