Characterization of the mouse Smad1 gene and its expression pattern in adult mouse tissues

Smad1 belongs to a family of receptor-activated proteins which mediate sign als from TGF-beta superfamily ligands, including TGF-beta and BMPs. Althoug h much is known about the biochemistry of Smad1 signal transduction, the ro le of Smad1 in vivo is still unclear. Here we present the first description of the genomic structure of the mouse Smad1 gene and the characterization of its expression pattern in adult mouse tissues by immunohistochemistry. T he Smad1 gene contains 7 exons and spans >42 kb of genomic DNA. Its coding region is contained within 6 exons and all introns, except intron 1, follow the GT/AG rule. Immunohistochemical analysis shows that Smad1 is widely ex pressed in adult mouse tissues, with a varying degree of nuclear localizati on in different cell types, suggesting a regulated function for this protei n. This study assigns all of the exon-intron boundaries of the mouse Smad1 gene and provides the basis for assessing the functional significance of th is gene using targeted gene manipulation in the mouse. (C) 2000 Elsevier Sc ience B.V. All rights reserved.