Function of ets genes is conserved between vertebrates and Drosophila

Area of Science:

• Developmental Biology
• Molecular Genetics
• Transcriptional Regulation

Background:

• The Drosophila pointed gene produces two ETS transcriptional activators, pointedP1 and pointedP2, crucial for embryonic development.
• pointedP2 plays vital roles in midline glial cell differentiation in the central nervous system and photoreceptor cell differentiation in the eye.
• Vertebrate c-ets-1 and c-ets-2 genes share homologous ETS domains with Drosophila pointed, suggesting potential functional conservation.

Purpose of the Study:

• To investigate the functional homology between vertebrate ets genes and the Drosophila pointed gene.
• To determine the specific domains responsible for the conserved functions of ets and pointed genes.

Main Methods:

• In vitro binding assays using pointedP2 and an optimized c-Ets-1/c-Ets-2 probe.
• Transient expression of pointedP2 in vertebrate cells to assess stimulation of c-Ets-1/c-Ets-2-responsive sequences.
• Expression of vertebrate ets transgenes in Drosophila to rescue pointed mutant phenotypes.
• Ectopic expression of pointedP1 in Drosophila to rescue pointedP2 deficiency.

Main Results:

• Vertebrate ets genes are functionally homologous to Drosophila pointed.
• pointedP2 binds to and stimulates ets-responsive sequences in vertebrate cells.
• Vertebrate ets transgenes successfully rescue pointed mutant phenotypes in Drosophila midline glia and photoreceptor development.
• pointedP1 can rescue pointedP2 deficiency in photoreceptor development, highlighting functional redundancy.

Conclusions:

• The conserved ETS domain is the primary determinant for the functional phenocopying ability of ets products in vivo.
• The RII/pointed box, involved in ras-dependent signaling, is not essential for this conserved function.
• Vertebrate ets genes can substitute for Drosophila pointed function, underscoring a conserved mechanism in developmental regulation.