A Kunitz type protease inhibitor related protein is synthesized in Drosophila prepupal salivary glands and released into the moulting fluid during pupation

Insect Biochem Mol Biol. 2004 Aug;34(8):855-69. doi: 10.1016/j.ibmb.2004.05.006.


From the Drosophila virilis late puff region 31C, we microcloned two neighbouring genes, Kil-1 and Kil-2, that encode putative Kunitz serine protease inhibitor like proteins. The Kil-1 gene is expressed exclusively in prepupal salivary glands. Using a size mutant of the KIL-1 protein and MALDI-TOF analysis, we demonstrate that during pupation this protein is released from the prepupal salivary glands into the pupation fluid covering the surface of the pupa. 3-D-structure predictions are consistent with the known crystal structure of the human Kunitz type protease inhibitor 2KNT. This is the first experimental proof for the extracorporal presence of a distinct Drosophila prepupal salivary gland protein. Possible functions of KIL-1 in the context of the control of proteolytic activities in the pupation fluid are discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Aprotinin / chemistry*
  • Base Sequence
  • Cloning, Molecular
  • Drosophila / genetics*
  • Drosophila / growth & development
  • Endopeptidases / metabolism
  • Evolution, Molecular
  • Genes, Insect / genetics
  • Larva / enzymology
  • Larva / genetics
  • Larva / metabolism*
  • Molecular Sequence Data
  • Physical Chromosome Mapping
  • Pupa / genetics
  • Pupa / metabolism
  • Salivary Glands / growth & development*
  • Salivary Glands / metabolism*
  • Salivary Proteins and Peptides / chemistry
  • Salivary Proteins and Peptides / genetics
  • Salivary Proteins and Peptides / metabolism*
  • Sequence Analysis, Protein
  • Trypsin Inhibitors / chemistry
  • Trypsin Inhibitors / genetics
  • Trypsin Inhibitors / metabolism*


  • Salivary Proteins and Peptides
  • Trypsin Inhibitors
  • Aprotinin
  • Endopeptidases