Neural crest-specific and general expression of distinct metalloprotease-disintegrins in early Xenopus laevis development

Metalloprotease-disintegrins are a family of membrane-anchored glycoprotein s that have been implicated in diverse cellular processes, including fertil ization and myoblast fusion, release of TNF alpha from the plasma membrane, and neurogenesis. Here we report the cloning of cDNAs encoding three full- length (xMDC9, xMDC11b, and xMDC13), and one partial (xMDC11a) metalloprote ase-disintegrin from the amphibian Xenopus laevis, and the analysis of thei r expression during early X. laevis development and in adult tissues. The m ost notable finding was the highly localized and specific expression patter n of xmdc11a at the tailbud stage in the cranial neural crest and in a subs et of neural tube cells in the trunk region. In contrast, expression of the closely related xmdc11b was not detectable during the early stages of X. l aevis development, and remained low in the adult tissues examined here. Dis tinct expression patterns were also observed for two other highly related X . laevis genes, xmdc13 and adam13 (Alfandari et al., 1997). While adam13 is expressed in the semitic mesoderm and in neural crest cells, but not in ad ult testis, xmdc13 expression is low and ubiquitous in the developing embry o, but is clearly present in adult testis. Finally, xmdc9, the putative ort hologue of human and mouse mdc9, was found at all stages of development, an d in ail tissues examined, suggesting a function that may be utilized by mo st or all cells. The noteworthy features of these four xmdc genes and the i mplications of their distinct spatial and temporal expression patterns are discussed. (C) 1998 Academic Press.