Specific protein modifications are altered in a temperature-sensitive Drosophila developmental mutant.

Area of Science:

• Developmental Biology
• Molecular Genetics
• Biochemistry

Background:

• The temperature-sensitive Drosophila mutation l(3)c21RRW630 affects oogenesis, imaginal disc development, and embryogenesis.
• Previous studies indicated maternal effects on embryogenesis.

Purpose of the Study:

• To investigate the molecular basis of the developmental defects caused by the l(3)c21RRW630 mutation.
• To correlate observed morphological defects with altered molecular processes.

Main Methods:

• Two-dimensional gel electrophoresis was used to analyze protein synthesis in mutant Drosophila tissues at a restrictive temperature.
• Comparative analysis of partial proteolytic digests was performed to assess protein similarity.

Main Results:

• Mutant tissues showed elevated synthesis of three proteins and reduced synthesis of three other proteins compared to wild-type.
• Proteins with increased synthesis were found to be similar to those with reduced synthesis, suggesting a modification relationship.
• The wild-type c21R gene is proposed to encode a protein-modifying enzyme responsible for the acidic modification of three abundant proteins.

Conclusions:

• The c21R gene product is a protein-modifying enzyme essential for cell division, motility, and adult structure formation.
• Improper enzyme function in the mutant leads to the accumulation of unmodified substrate proteins, causing developmental defects.
• This study links morphological abnormalities in a Drosophila mutant to a specific molecular defect in protein modification.