Expression and a novel function of fi lamin-240 in lamellocyte development in Drosophila

Drosophila has a very effective innate immune system with striking similarities to innate immunity in vertebrates. Cel-lular immune defense in Drosophila is mediated by three different classes of hemocytes: the plasmatocytes, the lamel-locytes and the crystal cells. Lamellocytes represent a unique population of hemocytes, both in terms of morphology and function. The lamellocytes are large, flat, adherent cells, involved in encapsulation and neutralization of intruders or of abnormally developed tissues, too large to be engulfed by plasmatocytes. These cells are nonphagocytic and their cytoplasmic constituents are relatively sparse. Very few lamellocytes are observed in wild-type Oregon-R larvae. Parasitization by the Hymenopteran wasp, Leptopilinia bou-lardi, initiates the rapid differentiation of lamellocytes, which subsequently adhere to and surround the egg capsule. Thi