Connexin57 in normal and pathological development of mouse heart and greatarteries

Cx37 is a member of the connexin family of gap junction proteins, whose dis tribution in heart remains controversial. We have generated novel antibodie s against Cx37 to investigate this distribution during normal and pathologi cal development in mouse. Using these affinity-purified antibodies, we have detected Cx37 in hearts and aortas of mouse embryos from day 11 ed. onward s. Immunostaining revealed that during prenatal development Cx37 predominat ed in endothelial and endocardial cells but was also detectable in small am ounts in the trabeculated and compact layers of ventricular myocardium, as well as in the mesenchyme of conotruncal ridges and atrioventricular cushio ns. Cx37 was also differentially expressed in the ascending and descending portions of the embryonic aorta, according to a pattern which differed in t he three layers of the vessel wall. Cx37 distribution was altered in both h eart and aorta of mice that had been exposed to all-trans retinoic acid at the beginning of foetal development, whether or not these animals subsequen tly developed a transposition of great arteries. The data indicate that Cx3 7 is widely distributed in multiple compartments of cardiovascular system, in patterns which are modulated during development, by retinoic acid. Dev D yn 2000; 218:331-344. (C) 2000 Wiley-Liss, Inc.