Previous Article | Next Article ![]()
Mol. Cell. Biol., Oct 1997, 6057-6067, Vol 17, No. 10
B Luo, JC Aster, RP Hasserjian, F Kuo and J Sklar
Signaling through Notch receptors has been implicated in the control of
cellular differentiation in animals ranging from nematodes to humans.
Starting from a human expressed sequence tag-containing sequence resembling
that of Serrate, the gene for a ligand of Drosophila melanogaster Notch, we
assembled a full-length cDNA, now called human Jagged2, from overlapping
cDNA clones. The full-length cDNA encodes a polypeptide having extensive
sequence homology to Serrate (40.6% identity and 58.7% similarity) and even
greater homology to several putative mammalian Notch ligands that have
subsequently been described. When in situ hybridization was performed,
expression of the murine Jagged2 homolog was found to be highest in fetal
thymus, epidermis, foregut, dorsal root ganglia, and inner ear. In Northern
blot analysis of RNA from tissues of 2-week-old mice, the 5.0-kb Jagged2
transcript was most abundant in heart, lung, thymus, skeletal muscle,
brain, and testis. Immunohistochemistry revealed coexpression of Jagged2
and Notch1 within thymus and other fetal murine tissues, consistent with
interaction of the two proteins in vivo. Coculture of fibroblasts
expressing human Jagged2 with murine C2C12 myoblasts inhibited myogenic
differentiation, accompanied by increased Notch1 and the appearance of a
novel 115-kDa Notch1 fragment. Exposure of C2C12 cells to Jagged2 led to
increased amounts of Notch mRNA as well as mRNAs for a second Notch
receptor, Notch3, and a second Notch ligand, Jagged1. Constitutively active
forms of Notchl in C2C12 cells also induced increased levels of the same
set of mRNAs, suggesting positive feedback control of these genes initiated
by binding of Jagged2 to Notch1. This feedback control may function in vivo
to coordinate differentiation across certain groups of progenitor cells
adopting identical cell fates.
Copyright © 1997, American Society for Microbiology
Isolation and functional analysis of a cDNA for human Jagged2, a gene encoding a ligand for the Notch1 receptor
Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»