The 62E early-late puff of Drosophila contains D-spinophilin, an ecdysone-inducible PDZ-domain protein dynamically expressed during metamorphosis.
At the onset of metamorphosis in Drosophila melanogaster, the steroid hormone 20-OH ecdysone induces a small number of early and early-late puffs in the polytene chromosomes of the third-instar larval salivary gland whose activity is required for regulating the activity of a larger set of late puffs. Most of the corresponding early and early-late genes have been found to encode transcription factors that regulate a much larger set of late genes. In contrast, we describe here the identification of an ecdysone-regulated gene in the 62E early-late puff, denoted D-spinophilin, that encodes a protein similar to the mammalian protein spinophilin/neurabin II. The D-spinophilin protein is predicted to contain a highly conserved PP1-binding domain and adjacent PDZ domain, as well as a coiled-coil domain and SAM domain, and belongs to a family of related proteins from diverse organisms. Transcription of D-spinophilin is correlated with 62E puff activity during the early stages of metamorphosis and is ecdysone-dependent, making this the first member of this gene family shown to be regulated by a steroid hormone. Examination of the dynamic patterns of D-spinophilin expression during the early stages of metamorphosis are consistent with a role in central nervous system metamorphosis as well as a more general role in other tissues. As D-spinophilin appears to be the only member of this gene family in Drosophila, its study provides an excellent opportunity to elucidate the role of an important adaptor protein in a genetic model organism.
Department of Biological Sciences and Program in Medical Sciences, The Florida State University, Tallahassee, FL 32306-4370, USA.
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Keegan
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Schmerer
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Ring
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Garza
D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D015139:Blotting, Southern; D002875:Chromosomes / Q000378:metabolism; D020451:Contig Mapping; D018076:DNA, Complementary / Q000378:metabolism; D004330:Drosophila / Q000235:genetics*; D004440:Ecdysone / Q000378:metabolism; D004441:Ecdysterone / Q000378:metabolism; D017403:In Situ Hybridization; D007814:Larva / Q000378:metabolism; D008675:Metamorphosis, Biological / Q000235:genetics* / Q000502:physiology; D008840:Microfilament Proteins / Q000737:chemistry*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D005810:Multigene Family; D009419:Nerve Tissue Proteins / Q000737:chemistry*; D010749:Phosphoprotein Phosphatases / Q000737:chemistry; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013997:Time Factors; D014158:Transcription, Genetic; D000099273:Neurabins
D018076:DNA, Complementary; D004440:Ecdysone; D004441:Ecdysterone; D008840:Microfilament Proteins; D009419:Nerve Tissue Proteins; D010749:Phosphoprotein Phosphatases; D012333:RNA, Messenger; D000099273:Neurabins