Molecular cloning of Soli E2: an elastase-like serine proteinase from the imported red fire ant (Solenopsis invicta)

The 4th instar larva of the imported red fire ant, Solenopsis invicta, poss esses several serine proteinases, one of which, referred to as Soli E2, has been found to contain elastase-like activity. A cDNA Library was construct ed in lambda gt10 using Poly(A)(+)RNA from these larvae and a synthetic deg enerate oligonucleotide probe corresponding to a sequence encoding the N-te rminal of Soli E2 was utilized to screen the Library. Two clones were obtai ned covering the entire coding region of Soli E2, and the predicted structu re of this proteinase indicated that it was synthesized as a preproenzyme o f 249 amino acids, which was cleaved to give the mature form of 226 residue s. In addition, both clones showed identity to the N-terminal amino acid se quence obtained from Edman degradation of the mature purified proteinase. S ignificantly, Northern blot analysis of the different developmental stages revealed that Soli E2 was selectively expressed in the 4th instar larvae. ( C) 1999 Elsevier Science Ltd. All rights reserved.