The 616-amino acid human semaphorin E contains an N-terminal signal sequence of 15 amino acids that is followed by a semaphorin domain. In vitro translation of the semaphorin E cDNA yielded a 70-kD protein. The authors showed that semaphorin E is secreted by mammalian cells. By Northern blot analysis, semaphorin E was expressed as a 5.2-kb transcript in all human tissues tested.
CDDP-sensitive cells transfected with semaphorin E cDNA acquired CDDP-resistance. Semaphorin E was overexpressed in CDDP-resistant cell lines and was induced by diverse chemotherapeutic drugs and by x-ray and UV irradiation. Aberrant semaphorin E protein expression was detected immunohistochemically