Loss of putzig Activity Results in Apoptosis during Wing Imaginal Development in Drosophila

PLoS One. 2015 Apr 20;10(4):e0124652. doi: 10.1371/journal.pone.0124652. eCollection 2015.

Abstract

The Drosophila gene putzig (pzg) encodes a nuclear protein that is an integral component of the Trf2/Dref complex involved in the transcription of proliferation-related genes. Moreover, Pzg is found in a complex together with the nucleosome remodeling factor NURF, where it promotes Notch target gene activation. Here we show that downregulation of pzg activity in the developing wing imaginal discs induces an apoptotic response, accompanied by the induction of the pro-apoptotic gene reaper, repression of Drosophila inhibitor of apoptosis protein accumulation and the activation of the caspases Drice, Caspase3 and Dcp1. As a further consequence 'Apoptosis induced Proliferation' (AiP) and 'Apoptosis induced Apoptosis' (AiA) are triggered. As expected, the activity of the stress kinase Jun N-terminal kinase (JNK), proposed to mediate both processes, is ectopically induced in response to pzg loss. In addition, the expression of the mitogen wingless (wg) but not of decapentaplegic (dpp) is observed. We present evidence that downregulation of Notch activates Dcp1 caspase and JNK signaling, however, neither induces ectopic wg nor dpp expression. In contrast, the consequences of Dref-RNAi were largely indistinguishable from pzg-RNAi with regard to apoptosis induction. Moreover, overexpression of Dref ameliorated the downregulation of pzg compatible with the notion that the two are required together to maintain cell and tissue homeostasis in Drosophila.

MeSH terms

  • Animals
  • Apoptosis* / genetics
  • Cell Cycle Proteins / deficiency*
  • Cell Cycle Proteins / metabolism
  • Cell Proliferation
  • Cell Survival
  • Drosophila Proteins / deficiency*
  • Drosophila Proteins / metabolism
  • Drosophila melanogaster / cytology*
  • Drosophila melanogaster / genetics
  • Drosophila melanogaster / growth & development*
  • Epistasis, Genetic
  • Gene Silencing
  • Genes, Insect
  • Imaginal Discs / cytology
  • Imaginal Discs / growth & development*
  • JNK Mitogen-Activated Protein Kinases / metabolism
  • Larva / genetics
  • Mutation / genetics
  • Receptors, Notch / metabolism
  • Signal Transduction / genetics
  • Stress, Physiological / genetics
  • Transcription Factors / metabolism
  • Wings, Animal / cytology*
  • Wings, Animal / growth & development

Substances

  • Cell Cycle Proteins
  • Dref protein, Drosophila
  • Drosophila Proteins
  • N protein, Drosophila
  • Receptors, Notch
  • Transcription Factors
  • pzg protein, Drosophila
  • JNK Mitogen-Activated Protein Kinases

Grants and funding

The authors have no support or funding to report.