Essential and neural transcripts from the Drosophila shaking-B locus are differentially expressed in the embryonic mesoderm and pupal nervous system.
The shaking-B gene of Drosophila encodes two functions: one specifically neural and the other required for viability. Flies carrying neural mutations show a range of defects, the best characterized of which is a disruption of some synapses in the giant fibre system, while mutations in the essential function cause animals to die as first instar larvae. We have characterised an essential transcript from this locus and show that mutant lesions underlying two lethal shaking-B alleles map to its coding sequence. We also propose a new model for the topologies of Shaking-B proteins and their relatives. Essential shaking-B transcripts are found in embryonic mesodermal derivatives, while during metamorphosis both essential and neural transcripts are dynamically expressed in the pupal nervous system. Although the expression patterns of these transcripts overlap in many cells, only the neural form is expressed in the giant fibre cell bodies and the lamina and medulla of the optic lobes. This observation correlates with the phenotypes of mutations which disrupt the coding region of this neural transcript. On the basis of the expression patterns of shaking-B transcripts and the phenotypes conferred by mutations of shaking-B and homologous genes, we suggest that Shaking-B proteins and their homologues may be involved in the organisation of cellular membranes.
Crompton
D
D
School of Biological Sciences, Sussex University, Falmer, Brighton, United Kingdom.
Todman
M
M
Wilkin
M
M
Ji
S
S
Davies
J
J
D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D029742:Caenorhabditis elegans Proteins; D002462:Cell Membrane / Q000378:metabolism; D017630:Connexins; D018076:DNA, Complementary / Q000235:genetics; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics* / Q000254:growth & development; D004625:Embryo, Nonmammalian / Q000378:metabolism; D004924:Escape Reaction / Q000502:physiology; D017952:Ganglia, Invertebrate / Q000254:growth & development; D018507:Gene Expression Regulation, Developmental; D005804:Genes, Lethal; D015801:Helminth Proteins / Q000235:genetics; D017403:In Situ Hybridization; D007301:Insect Hormones / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D007422:Intestines / Q000196:embryology; D007814:Larva; D008565:Membrane Proteins / Q000235:genetics; D008648:Mesoderm / Q000378:metabolism; D008957:Models, Genetic; D008969:Molecular Sequence Data; D005810:Multigene Family; D009132:Muscles / Q000196:embryology; D009412:Nerve Fibers / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D009420:Nervous System / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D016366:Open Reading Frames; D010641:Phenotype; D017434:Protein Structure, Tertiary; D011679:Pupa / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D029742:Caenorhabditis elegans Proteins; D017630:Connexins; D018076:DNA, Complementary; D029721:Drosophila Proteins; D015801:Helminth Proteins; D007301:Insect Hormones; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C094444:Unc-7 protein, C elegans; C079326:ogre protein, Drosophila; C079324:shakB protein, Drosophila