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Sec61beta, a subunit of the protein translocation channel, is required during Drosophila development

R Valcárcel1, U Weber, D B Jackson

  • 1Developmental Biology, Instrumentation Programme, European Molecular Biology Laboratory, Meyerhofstrasse 1, D-69117 Heidelberg, Germany.

Journal of Cell Science
|November 24, 1999
PubMed

Insights

DSec61beta, a protein translocation channel subunit, is essential for Drosophila development, unlike its counterparts in yeast and E. coli. Mutations cause embryonic lethality and defects in protein secretion, highlighting its critical role in multicellular organisms.

Area of Science:

  • Cell Biology
  • Developmental Biology
  • Genetics

Background:

  • The Sec61 complex facilitates protein translocation across membranes.
  • Sec61beta homologs in yeast and E. coli are not essential for viability.
  • The role of Sec61beta in higher eukaryotes is largely unknown.

Purpose of the Study:

  • To investigate the function of DSec61beta, the Drosophila melanogaster homolog of Sec61beta.
  • To determine the essentiality of DSec61beta in a multicellular organism.

Main Methods:

  • Isolation and characterization of DSec61beta mutations in Drosophila.
  • Analysis of homozygous mutant embryos and germ line clones.
  • Clonal analysis in imaginal discs.

Main Results:

  • DSec61beta is essential for embryonic development, with homozygous mutants dying at late stages.
  • Mutant embryos exhibit impaired cuticle protein secretion and defects in dorso-ventral patterning due to affected Gurken secretion.
  • Clonal analysis reveals defects in adult structures like rhabdomere morphogenesis and reduced tarsal segment size.

Conclusions:

  • DSec61beta plays a critical, essential role in Drosophila development, contrasting with its non-essential function in unicellular organisms.
  • This study demonstrates how a protein with a kinetic function in single-cell organisms can become vital for complex multicellular development.
  • DSec61beta is crucial for proper secretion of key developmental proteins and morphogenesis in Drosophila.

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