Developmental patterns of ceramide glucosyltransferase (GlcT-1) expressionin the mouse: In situ hybridization using DIG-labeled RNA probes

Glycosphingolipids (GSLs) play significant roles in a variety of cell membr ane events, including cellular interactions, signaling, and trafficking. Ce ramide glucosyltransferase (glucosylceramide synthase, GlcT-1, EC 2.4.1.80) catalyzes the initial step in GSL synthesis, the transfer of glucose from UDP-glucose to ceramide, The reaction product of glucosylceramide serves as a core structure for over 400 species of GSLs, The enzyme is a key regulat ory factor controlling intracellular levels of ceramide and GSLs. Appearanc e and differenfial distribution of GlcT-1 mRNA during mice postimplantation embryogenesis [embryonic (E) days; E9, E1I, E13, E15] were investigated by in situ hybridization with digoxigenin-labeled RNA probes, coupled with al kaline phosphatase detection. On E9, tissues:of the mesencephalon, myelecep halon, dience-phalons, and telencephalon expressed GlcT-1. On E11, if Tvas expressed to a detectable extent in various tissues including mesencephalon , myelece-phalon, diencephalon, telencephalon, nose, lung, liver, vertebra, tail, spinal cord, and tongue. The expression patterns of E13 were similar to those of E11, except that the heart and stomach became positive. On E15 , a specific signal for GlcT-1 was detected in all organs of the embryo, Th ese results provide the first evidence that GlcT-1 is differentially expres sed during postimplantation embryogenesis.