Establishment of transgenic silkworms expressing GAL4 specifically in the haemocyte oenocytoid cells

Insect Mol Biol. 2014 Apr;23(2):165-74. doi: 10.1111/imb.12071. Epub 2013 Nov 15.

Abstract

Insect haemocytes play significant roles in innate immunity. The silkworm, a lepidopteran species, is often selected as the model for studies into the functions of haemocytes in immunity; however, our understanding of the role of haemocytes remains limited because the lack of haemocyte promoters for transgene expression makes genetic manipulations difficult. In the present study, we aimed to establish transgenic silkworm strains expressing GAL4 in their haemocytes. First, we identified three genes with strong expression in haemocytes, namely, lp44, Haemocyte Protease 1 (HP1) and hemocytin. Transgenic silkworms expressing GAL4 under the control of the putative promoters of these genes were then established and expression was examined. Although GAL4 expression was not detected in haemocytes of HP1-GAL4 or hemocytin-GAL4 strains, lp44-GAL4 exhibited a high level of GAL4 expression, particularly in oenocytoids. GAL4 expression was also detected in the midgut but in no other tissues, indicating that GAL4 expression in this strain is mostly oenocytoid-specific. Thus, we have identified a promoter that enables oenocytoid expression of genes of interest. Additionally, the lp44-GAL4 strain could also be used for other types of research, such as the functional analysis of genes in oenocytoids, which would facilitate advances in our understanding of insect immunity.

Keywords: GAL4; haemocyte; oenocytoid; promoter identification; transgenic silkworm.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Genetically Modified / genetics
  • Animals, Genetically Modified / immunology
  • Animals, Genetically Modified / metabolism
  • Bombyx / genetics*
  • Bombyx / growth & development
  • Bombyx / immunology
  • Bombyx / metabolism
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism
  • Gene Expression Regulation*
  • Hemocytes / metabolism*
  • Immunity, Innate
  • Insect Proteins / genetics*
  • Insect Proteins / metabolism
  • Larva / genetics
  • Larva / immunology
  • Larva / metabolism
  • Lectins / genetics
  • Lectins / metabolism
  • Promoter Regions, Genetic
  • Reverse Transcriptase Polymerase Chain Reaction
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae Proteins / genetics*
  • Saccharomyces cerevisiae Proteins / metabolism
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism

Substances

  • DNA-Binding Proteins
  • GAL4 protein, S cerevisiae
  • Insect Proteins
  • Lectins
  • Saccharomyces cerevisiae Proteins
  • Transcription Factors
  • hemocytin protein, Bombyx mori