A Genetic Screen in Drosophila for Genes Interacting With senseless During Neuronal Development Identifies the Importin moleskin

Abstract

Senseless (Sens) is a conserved transcription factor required for normal development of the Drosophila peripheral nervous system. In the Drosophila retina, sens is necessary and sufficient for differentiation of R8 photoreceptors and interommatidial bristles (IOBs). When Sens is expressed in undifferentiated cells posterior to the morphogenetic furrow, ectopic IOBs are formed. This phenotype was used to identify new members of the sens pathway in a dominant modifier screen. Seven suppressor and three enhancer complementation groups were isolated. Three groups from the screen are the known genes Delta, lilliputian, and moleskin/DIM-7 (msk), while the remaining seven groups represent novel genes with previously undefined functions in neural development. The nuclear import gene msk was identified as a potent suppressor of the ectopic interommatidial bristle phenotype. In addition, msk mutant adult eyes are extremely disrupted with defects in multiple cell types. Reminiscent of the sens mutant phenotype, msk eyes demonstrate reductions in the number of R8 photoreceptors due to an R8 to R2,5 fate switch, providing genetic evidence that Msk is a component of the sens pathway. Interestingly, in msk tissue, the loss of R8 fate occurs earlier than with sens and suggests a previously unidentified stage of R8 development between atonal and sens.

The enhancer of trithorax and polycomb gene Caf1/p55 is essential for cell survival and patterning in Drosophila development

“…Caf1 alleles generated in our laboratory were reported previously as S(ls)3 (Pepple et al, 2007). The Caf1 Genomic Rescue construct (Caf1GR) was generated by recombineering a fragment from BACR32A03 into pACMAN (Venken et al, 2006).…”

“…For histone methylation staining experiments, discs were dissected and stained as described previously (Fan and Bergmann, 2010). For all other staining experiments, eye-antennal imaginal discs were dissected and stained, and images acquired, as described previously (Pepple et al, 2007). Adobe Photoshop and Gimp software were used to process image brightness, color, contrast and noise, and to merge channels.…”

“…This disruption is caused, in part, by formation of extra interommatidial bristles (Pepple et al, 2007). Previously, we have reported the isolation of a three-member lethal complementation group, S(ls)3, that was discovered in a screen for mutations that dominantly modify ls (Pepple et al, 2007).…”

“…Recently, we performed a screen in Drosophila for dominant modifiers of a disorganized eye phenotype caused by overexpression of senseless (Pepple et al, 2007). Here, we report the identification of the complementation group S(ls)3, comprising three loss-of-function alleles, as the first mutations in Drosophila Caf1.…”

The splicing factor Prp31 is essential for photoreceptor development in Drosophila

“…The Drosophila eye has served as a powerful system for screening for genes important for development (Pepple et al, 2007;Wolff et al, 2007). The observations that DmPrp31RNAi flies show dramatic eye defects and that the expression of human Prp31 partially rescues the eye defects indicate that DmPrp31 is required for the formation or maintenance of photoreceptors and that human and fly Prp31 genes are functionally equivalent in vivo.…”