The Neurofibromatosis 2 (NF2) gene is a member of the ezrin-radixin-moesin (ERM) family of cytoskeletal linkers, thought to be involved in tissue integrity. It is a classical tumor suppressor, predisposing for tumors when missing in one germline allele, and resulting in tumor formation when fully absent. Structural comparison demonstrates that the C. elegans ortholog
nfm-1 is highly conserved, and its genomic structure closely related to its human ortholog, particularly in the membrane-linking FERM (protein 4.1-ezrin-radixin-moesin) domain and the C-terminus. By -gal/GFP reporter analysis,
nfm-1, like its family member
erm-1 (the C. elegans ERM ortholog), is expressed in tubular organ epithelia: the pharynx, intestine, gonad arms, uterus and vulva. In contrast to the apically placed ERM-1, NFM-1 is localized to basolateral membranes. We isolated an
nfm-1 allele by PCR deletion screen (
nfm-1(
fg1)), which deletes ~1.4 kb of the 5 part of the gene, encoding the entire FERM domain, adds a small insertion, and generates a frameshift. This allele results in embryonic lethality and is likely a null allele. A second allele,
nfm-1(
ok754) (kindly provided by the Knockout Consortium), generates an in-frame deletion of ~1kb corresponding to exons 3-6, which encode the second half of the FERM domain. Homozygous progeny of
nfm-1(
ok754) III/hT2[qIs48] (I;III) and
nfm-1(
ok754)/sma-4
(e729)
mab-5(
e1239)
unc-36(
e251)III animals die as L1-L2 larvae.
nfm-1(
ok754) in trans to a deficiency behaves as a loss-of-function, not as a null allele.
nfm-1 RNAi does not phenocopy or show any other obvious phenotype. Rescue experiments of the two alleles are underway. We will show the distribution of a number of apical, basolateral, and junctional molecules in
nfm-1 mutants. We will further show TEM studies of
nfm-1 mutant embryos demonstrating severe early epithelial morphogenesis defects. Finally, we will present data investigating a possible interaction of
erm-1 and
nfm-1.