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)

To evaluate the developmental distribution of adrenergic cells in vivo, we inserted the Cre-recombinase gene into the locus encoding for the epinephrine biosynthetic enzyme phenylethanolamine n-methyltransferase (Pnmt) and crossed these Pnmt-Cre mice with ROSA26 reporter (R26R) mice to activate LacZ (encoding beta-galactosidase) expression in cells that were selectively derived from the adrenergic lineage. Our data show the following: (1) Insertion of Cre-recombinase into the Pnmt locus created a functional knockout of Pnmt expression with concomitant loss of epinephrine in homozygous Pnmt(Cre/Cre) mice; (2) Despite the reduction in Pnmt expression and epinephrine production in Pnmt(Cre/Cre) mice, these mice were viable and fertile, with no apparent developmental defects; (3) When crossed with R26R mice, Pnmt-Cre activation of LacZ expression faithfully recapitulated Pnmt expression in vivo; and (4) LacZ expression was activated in substantial numbers of pacemaking, conduction, and working cardiomyocytes.
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PMID:Targeted insertion of the Cre-recombinase gene at the phenylethanolamine n-methyltransferase locus: a new model for studying the developmental distribution of adrenergic cells. 1551 85

The heart is a primary source of epinephrine and norepinephrine during embryonic development, yet little is known about the cardiac cells that produce these catecholamine hormones. To identify when and where catecholamine-synthesizing cells are found in the embryonic heart, we developed a novel mouse genetic model by "knocking-in" the Cre-recombinase gene to the locus encoding for the epinephrine biosynthetic enzyme, phenylethanolamine n-methyltransferase. When crossed with ROSA26 reporter mice, the beta-galactosidase gene is activated in adrenergic cells. A major advantage of this approach is that it allows detection of adrenergic cells and their progeny, regardless of whether the progeny cells retain an adrenergic phenotype or not. Our data show that adrenergic cells appear as early as embryonic day 8.5 and continue to accumulate in substantial numbers through birth in the mouse heart, where they appear to share common ancestry with myocardial lineages. Large numbers of atrial and especially ventricular myocytes appear to be derived from embryonic adrenergic cells in the heart. In addition, many of the pacemaking cells in the sinoatrial and atrioventricular nodes also appear to be derived from an adrenergic lineage. Thus, our results suggest that catecholamine-synthesizing cells serve as cardiomyocyte progenitors in the embryonic heart.
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PMID:Catecholamine-synthesizing cells in the embryonic mouse heart. 1912 Jan 24