Embryonic expression of type XIX collagen is transient and confined to muscle cells

Type XIX collagen is a poorly characterized extracellular matrix component thought to be involved in the formation of specialized basement membrane zo nes. Here we examined the developmental expression of the mouse gene (Col19 a1) by in situ hybridization, Col19a1 expression during embryogenesis comme nces at similar to E9.5 in the myotome and with a pattern that closely foll ows the myogenic regulatory factor myf-5, Like myf-5, Col19a1 transcription gradually decreases in differentiating skeletal muscle progenitors and con comitantly to increased myogenin gene expression. Transient expression of C ol19a1 in muscular tissues is confined to a few sites of the developing emb ryo, such as limbs, tongue, and the smooth muscle layers of the stomach and esophagus, Additional non-muscular sites of Col19a1 activity include the s kin of the E16.5 embryos and the cerebral cortex and hippocampus of the new born brain, Unlike all other tissues, expression of Col19a1 in the central nervous system gradually increases after birth, (C) 2001 Wiley-Liss, Inc.