ISOLATION OF THE HUMAN SEMAPHORIN III F GENE (SEMA3F) AT CHROMOSOME 3P21, A REGION DELETED IN LUNG-CANCER/

Small cell lung cancer (SCLC) has been correlated with a deletion in t he short arm of chromosome 3, with the region 3p21 being lost from one homolog in almost all cases. Two SCLC cell lines have homozygous dele tions in 3p21, and these deletions overlap with a fragment of chromoso me 3 that has tumor suppression activity in vivo. We have isolated som e cDNA clones from this region that are homologous to the genes consti tuting the semaphorin family. They represent a novel human semaphorin, termed sema III/F (HGMW-approved symbol SEMA3F), which is expressed a s a 3.8-kb transcript in a variety of cell lines and tissues; it is de tected as early as Embryonic Day 10 in mouse development. There is hig h expression in mammary gland, kidney, fetal brain, and lung and lower expression in heart and liver. Although there is reduced expression o f this gene in several SCLC lines, no mutations were found. This semap horin homolog has characteristics of a secreted member of the semaphor in III family, with 52% identity with mouse semaphorin E and 49% ident ity with chicken collapsin/semaphorin D. (C) 1996 Academic Press, Inc.