The ADAM gene family encodes multidomain proteins, which contain a transmembrane domain and both A D isintegrin A nd M etalloprotease domains. Members of the ADAM family were previously shown to be involved in cell-cell adhesion, cell migration and organ formation. ADM-1 was the first reported ADAM member in C. elegans , and was shown to express in several tissues including sperm, plasma membrane of embryonic cells and sheath cells of sensory organs. Western blots using the monoclonal Ab against the cytoplasmic tail of ADM-1 (17B7) and polyclonal Abs against the extracellular domain have previously shown the proteolytical processing of ADM-1 from a precursor to a mature form (1). Molecular analysis of
unc-71 mutants has shown molecular defects in the
adm-1 locus (Yishi Jin and Xun Huang personal communication*).
unc-71 is involved in one of the pathways of sex myoblast migration and in axon outgrowth (2). Immunoflourescence, immunopercipitation and western blots are being used to analyze the specific protein expression of
adm-1/unc-71 mutants. The
adm-2 gene was cloned and sequenced in our lab (3). An
adm-2::gfp construct was shown to be expressed in the whole embryo at early stages.
adm-2::GFP expression is limited to the nerve ring, ventral and dorsal nerve cord and the CAN neurons in larvae and adults. Recently, a mutant strain carrying a deletion of the
adm-2 gene has become available to us (
tm347*). We are conducting genetic crosses with strains carrying a
mec-2::gfp
unc25::gfp and
adm-2::gfp constructs in order to reveal differences in the pattern of neuron morphology, migration and organization in this mutant strain that appears morphologically wild-type. We are also using RNAi of
adm-1 and
adm-2 on N2 animals, as well as on both mutants in order to reveal any interaction between these genes. We will discuss our biochemical and genetic studies on the characterization of
adm-1 and
adm-2 . * We gratefully acknowledge Yishi Jin, Xun Huang and Michael Stern for
unc-71 alleles and Shohei Mitani and Yuji Kohara for the
adm-2 deletion mutant. (1) Podbilewicz (1996) MBC 7, 1877 (2) Chen and Stern (1998) TIG 14, 322 (3) Adir (1999) 12 th International C. elegans Meeting: 140