Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tropomodulins are a family of proteins that cap the slow-growing end of actin filaments. Erythrocyte tropomodulin (E-Tmod) stabilizes short actin protofilaments in erythrocytes and caps longer sarcomeric actin filaments in striated muscles. We report the knockin of the beta-galactosidase gene (LacZ) under the control of the endogenous E-Tmod promoter and the knockout of E-Tmod in mouse embryonic stem cells. E-Tmod(-/-) embryos die around embryonic day 10 and exhibit a noncontractile heart tube with disorganized myofibrils and underdevelopment of the right ventricle, accumulation of mechanically weakened primitive erythroid cells in the yolk sac, and failure of primary capillary plexuses to remodel into vitelline vessels, all required to establish blood circulation between the yolk sac and the embryo proper. We propose a hemodynamic "plexus channel selection" mechanism as the basis for vitelline vascular remodeling. The defects in cardiac contractility, vitelline circulation, and hematopoiesis reflect an essential role for E-Tmod capping of the actin filaments in both assembly of cardiac sarcomeres and of the membrane skeleton in erythroid cells that is not compensated for by other proteins.
 ...
PMID:E-Tmod capping of actin filaments at the slow-growing end is required to establish mouse embryonic circulation. 1254 41

Erythrocyte tropomodulin (E-Tmod, Tmod1) is a tropomyosin-binding protein that caps the slow-growing end of actin filaments. In erythrocytes, it may favor the formation of short actin protofilaments needed for elastic cell deformation. Previously we created a knockout mouse model in which lacZ was knocked-in downstream of the E1 promoter to report the expression of full length E-Tmod. Here we utilize E-Tmod(+/lacZ) mice to study E-Tmod expression patterns in the CNS. X-gal staining and in situ hybridization of adults revealed its restricted expression in the olfactory bulb, hippocampus, cerebral cortex, basal ganglia, nuclei of brain stem and cerebellum. In neonates, signals in the cortex and caudate putamen increased from days 15 to 40. Immunohistochemistry also revealed that signals for beta-galactosidase coincided with that of NeuN, a post-mitotic nuclear marker for neurons, but not that for GFAP+ astrocytes or APC+ oligodendrocytes, suggesting E-Tmod/lacZ-positive cells in the CNS were neurons. Large neurons, e.g., mitral cells in olfactory bulb and mossy cells in hilus of the dentate gyrus are among those that expressed very high levels of E-Tmod in the CNS.
 ...
PMID:Mouse erythrocyte tropomodulin in the brain reported by lacZ knocked-in downstream from the E1 promoter. 1792 Mar 39