"In vivo" toxicity of a truncated version of the Drosophila Rst-IrreC protein is dependent on the presence of a glutamine-rich region in its intracellular domain.
The roughest-irregular chiasm C ( rst-irreC) gene of Drosophila melanogaster encodes a transmembrane glycoprotein containing five immunoglobulin-like domains in its extracellular portion and an intracytoplasmic tail rich in serine and threonine as well some conserved motifs suggesting signal transduction activity. In the compound eye, loss-of-function rst-irreC mutants lack the characteristic wave of programmed cell death happening in early pupa and which is essential for the elimination of the surplus interommatidial cells. Here we report an investigation on the role played by the Rst-irreC molecule in triggering programmed cell death. "In vivo" transient expression assays showed that deletion of the last 80 amino acids of the carboxyl terminus produces a form of the protein that is highly toxic to larvae. This toxicity is suppressed if an additional 47 amino acid long, glutamine-rich region ("opa-like domain"), is also removed from the protein. The results suggest the possibility that the opa-like domain and the carboxyl terminus act in concert to modulate rst-irreC function in apoptosis, and we discuss this implication in the context of the general mechanisms causing glutamine-rich neurodegenerative diseases in humans.
Machado
Ricardo C
RC
Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, 14040-900.
Pereira
Rodrigo N R
RN
Costa
Mara S A
MS
Ramos
Ricardo Guelerman P
RG
D000596:Amino Acids / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D015816:Cell Adhesion Molecules, Neuronal / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D016923:Cell Death; D004330:Drosophila / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D005136:Eye Proteins; D005260:Female; D005973:Glutamine / Q000737:chemistry*; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D007814:Larva / Q000187:drug effects; D010957:Plasmids
D000596:Amino Acids; D015816:Cell Adhesion Molecules, Neuronal; D029721:Drosophila Proteins; D005136:Eye Proteins; D019476:Insect Proteins; C085209:rst protein, Drosophila; D005973:Glutamine