Mutations affecting the development of the peripheral nervous system in drosophila: A molecular screen for novel proteins

In our quest for novel genes required for the development of the embryonic peripheral nervous system (PNS), we have performed three genetic screens us ing MAb 22C10 as a marker of terminally differentiated neurons. A total of 66 essential genes required for normal PNS development were identified, inc luding 49 novel genes. To obtain information about the molecular nature of these genes, we decided to complement our genetic screens with a molecular screen. From transposon-tagged mutations identified on the basis of their p henotype in the PNS we selected 31 P-element strains representing 26 comple mentation groups on the second and third chromosomes to clone and sequence the corresponding genes. We used plasmid rescue to isolate and sequence 51 genomic fragments flanking the sites of these P-element insertions. Databas e searches using sequences derived from the ends of plasmid rescues allowed us to assign genes to one of four classes: (1) previously characterized ge nes (11), (2) first mutations in cloned genes (1), (3) P-element insertions in genes that were identified, hut not characterized molecularly (1), and (4) novel genes (13). Here, we report the cloning, sequence, Northern analy sis, and the embryonic expression pattern of candidate cDNAs for 10 genes: astray, chrowded, dalmatian, gluon, hoi-polloi, melted, pebble, skittles, s ticky ch1, and vegetable. This study allows us to draw conclusions about th e identity of proteins required for the development of the nervous system i n Drosophila and provides an example of a molecular approach to characteriz e en masse transposon-tagged mutations identified in genetic screens.