The Drosophila casein kinase Iepsilon/delta Discs overgrown promotes cell survival via activation of DIAP1 expression.
The proper number of cells in developing tissues is achieved by coordinating cell division with apoptosis. In Drosophila, the adult wing is derived from wing imaginal discs, which undergo a period of growth and proliferation during larval stages without much programmed cell death. In this report, we demonstrate that the Drosophila casein kinase Iepsilon/delta, known as Discs overgrown (Dco), is required for maintaining this low level of apoptosis. Expression of dco can suppress the apoptotic activity of Head involution defective (Hid) in the developing eye. Loss of dco in the wing disc results in a dramatic reduction in expression of the caspase inhibitor DIAP1 and a concomitant activation of caspases. The regulation of DIAP1 by Dco occurs by a post-transcriptional mechanism that is independent of hid. Mutant clones of dco are considerably smaller than controls even when apoptosis is inhibited, suggesting that Dco promotes cell division/growth in addition to its role in cell survival. The dco phenotype cannot be explained by defects Wingless (Wg) signaling. We propose that Dco coordinates tissue size by stimulating cell division/growth and blocking apoptosis via activation of DIAP1 expression.
Guan
Ju
J
Department of Molecular, Cellular and Developmental Biology, University of Michigan, Natural Science Building, Ann Arbor, MI 48109-1048, USA.
Li
Hui
H
Rogulja
Ana
A
Axelrod
Jeff D
JD
Cadigan
Ken M
KM
D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000502:physiology*; D048149:Casein Kinase 1 epsilon / Q000378:metabolism*; D002470:Cell Survival / Q000235:genetics / Q000502:physiology*; D017931:DNA Primers; D004330:Drosophila / Q000196:embryology* / Q000201:enzymology; D029721:Drosophila Proteins / Q000378:metabolism*; D005123:Eye / Q000196:embryology*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D020287:In Situ Nick-End Labeling; D051034:Inhibitor of Apoptosis Proteins / Q000378:metabolism*; D034622:RNA Interference / Q000502:physiology*; D019076:Transgenes / Q000235:genetics; D014921:Wings, Animal / Q000196:embryology*
C111891:DIAP1 protein, Drosophila; D017931:DNA Primers; D029721:Drosophila Proteins; D051034:Inhibitor of Apoptosis Proteins; C113519:dco protein, Drosophila; D048149:Casein Kinase 1 epsilon