Intercellular adhesivity and pupal morphogenesis inDrosophila melanogaster

Area of Science:

• Developmental biology
• Cell biology
• Insect morphology

Background:

• Imaginal discs in Drosophila melanogaster are larval structures that develop into adult appendages.
• Understanding the mechanisms of rapid morphogenesis is crucial for developmental biology.

Purpose of the Study:

• To investigate the role of intercellular adhesivity in the rapid shape changes of Drosophila imaginal discs.
• To determine if microtubules are essential for disc shape changes during simulated pupal morphogenesis.

Main Methods:

• Treatment of mature larval leg and wing imaginal discs with 0.1% trypsin.
• Observation of morphological changes in discs and epithelial cells.
• Treatment with Colcemid to depolymerize microtubules.
• Assessment of intercellular adhesivity and junction integrity.

Main Results:

• Trypsin treatment induced rapid shape changes in imaginal discs, mimicking pupal morphogenesis.
• Epithelial cells transformed from tall columnar to cuboidal.
• Colcemid treatment depolymerized microtubules but did not affect disc or cell shape.
• Tryptic digestion decreased non-junctional intercellular adhesivity, while desmosomes and gap junctions remained intact.

Conclusions:

• Drosophila imaginal discs possess a pre-packaged structure enabling rapid morphogenesis.
• Changes in intercellular adhesivity, not microtubules, appear to drive the rapid shape transformation.
• The disc's inherent structure facilitates the swift replacement of larval forms with adult integument.