Hermann Steller

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A gene, reaper (rpr), that appears to play a central control function for the initiation of programmed cell death (apoptosis) in Drosophila was identified. Virtually all programmed cell death that normally occurs during Drosophila embryogenesis was blocked in embryos homozygous for a small deletion that includes the reaper gene. Mutant embryos contained(More)
In many metazoans, damaged and potentially dangerous cells are rapidly eliminated by apoptosis. In Drosophila, this is often compensated for by extraproliferation of neighboring cells, which allows the organism to tolerate considerable cell death without compromising development and body size. Despite its importance, the mechanistic basis of such(More)
The deliberate and orderly removal of cells by programmed cell death is a common phenomenon during the development of metazoan animals. We have examined the distribution and ultrastructural appearance of cell deaths that occur during embryogenesis in Drosophila melanogaster. A large number of cells die during embryonic development in Drosophila. These cells(More)
Deletions of chromosomal region, 75C1,2 block virtually all programmed cell death (PCD) in the Drosophila embryo. We have identified a gene previously in this interval, reaper (rpr), which encodes an important regulator of PCD. Here we report the isolation of a second gene in this region, head involution defective (hid), which plays a similar role in PCD.(More)
Extracellular growth factors are required for the survival of most animal cells. They often signal through the activation of the Ras pathway. However, the molecular mechanisms by which Ras signaling inhibits the intrinsic cell death machinery are not well understood. Here, we present evidence that in Drosophila, activation of the Ras pathway specifically(More)
The steroid hormone ecdysone signals the stage-specific programmed cell death of the larval salivary glands during Drosophila metamorphosis. This response is preceded by an ecdysone-triggered switch in gene expression in which the diap2 death inhibitor is repressed and the reaper (rpr) and head involution defective (hid) death activators are induced. Here(More)
Stress in the endoplasmic reticulum (ER stress) and its cellular response, the unfolded protein response (UPR), are implicated in a wide variety of diseases, but its significance in many disorders remains to be validated in vivo. Here, we analyzed a branch of the UPR mediated by xbp1 in Drosophila to establish its role in neurodegenerative diseases. The(More)
Apoptosis is a morphologically distinct form of programmed cell death that plays a major role during development, homeostasis, and in many diseases including cancer, acquired immunodeficiency syndrome, and neurodegenerative disorders. Apoptosis occurs through the activation of a cell-intrinsic suicide program. The basic machinery to carry out apoptosis(More)
In Drosophila, the chromosomal region 75C1-2 contains at least three genes, reaper (rpr), head involution defective (hid), and grim, that have important functions in the activation of programmed cell death. To better understand how cells are killed by these genes, we have utilized a well defined set of embryonic central nervous system midline cells that(More)