Lethal P-lacZinsertion lines expressed during pattern respecification in the imaginal discs ofDrosophila

Abstract

The imaginal discs of Drosophila are a useful experimental system in which we can study the origin and genetic determination of spatial patterns in development. This involves the separation of the disc-cell population into distinct lineage compartments, based on clonally transmitted expression states of a number of known selector genes. However, these commitments can be abrogated and the compartment boundaries redeployed, when repatterning occurs in cultured disc fragments. This has so far only been explained using the idea of positional information. The genetic basis of this property of the imaginal disc system and its relationship to compartments have not been identified. Here we have screened over 470 recessive lethal P-lacZ enhancer-trap insertions from the Berkeley Drosophila Genome Project for expression after cell death, which initiates pattern respecification in the imaginal discs. The positive lines obtained identify essential genes that may be important for pattern formation. Most show patterned imaginal disc expression, and many have maternal or zygotic effects on embryonic development. One is an allele of schnurri, a gene that encodes a component of the decapentaplegic (dpp) signal transduction pathway used for positional signalling in the embryo and in imaginal discs.

Foxo and Fos regulate the decision between cell death and survival in response to UV irradiation

“…We tested whether the requirement for JNK in UV‐mediated apoptosis would correlate with transcriptional upregulation of pro‐apoptotic molecules. Using a lacZ reporter line (Russell et al , 1998; Cox et al , 2000; Cullen and McCall, 2004; Sen et al , 2004), we found rapid induction of hid transcription in response to genotoxic UV irradiation (Figure 2A). This induction, which we validated using RT–PCR on RNA extracted from irradiated retinae (Figure 2B), was not observed in hep 1 mutant animals (Figure 2B).…”

A screen for genes that function in leg disc regeneration in Drosophila melanogaster

“…Previously, 470 recessive lethal P-lacZ enhancer trap lines were screened for ectopic expression after imaginal disc injury and regeneration (Russell et al, 1998). In this study, Russell et al (1998) induced disc regeneration in vivo by random cell death using two different methods: (1) a temperature sensitive cell-lethal mutation in suppressor of forked [su(f) 12 ] and (2) a short exposure to gamma radiation.…”

“…In this study, Russell et al (1998) induced disc regeneration in vivo by random cell death using two different methods: (1) a temperature sensitive cell-lethal mutation in suppressor of forked [su(f) 12 ] and (2) a short exposure to gamma radiation. Out of the 470 PZ insertions, a total of 118 were identified with ectopic lacZ expression after gamma radiation, and 47 of those were also activated after su(f)-induced cell death (Russell et al, 1998).…”

“…We have performed a genetic screen aimed at identifying genes that regulate cellular plasticity and regeneration using Drosophila prothoracic leg discs. We screened a collection of 97 recessive lethal P-element lacZ (PZ) insertion lines (Russell et al, 1998) and identified six genes that function in wg-induced leg disc regeneration, including genes with functional ties to Wg signaling as well as chromatin remodeling proteins.…”

Cell death-induced regeneration in wing imaginal discs requires JNK signalling

“…The sophisticated genetic tools available for use in Drosophila, however, raise the possibility of investigating regeneration in situ without the need for mechanical manipulation. For example, a temperature-sensitive cell-autonomous lethal allele of suppressor of forked has been used to genetically induce cell death and regeneration in imaginal discs (Brook et al, 1993;Russell et al, 1998). Furthermore, cell death can be locally induced in certain domains of the disc using the Gal4/UAS binary system in combination with Gal80 ts (Zeidler et al, 2004) to transiently activate pro-apoptotic genes, thereby mimicking microsurgical ablation.…”