Project description:An animal’s skin provides a first point of contact with the sensory environment, including noxious cues that elicit protective behavioral responses. Nociceptive somatosensory neurons densely innervate and intimately interact with epidermal cells to receive these cues, however the mechanisms by which epidermal interactions shape processing of noxious inputs is still poorly understood. Here, we identify a role for dendrite intercalation between epidermal cells in tuning sensitivity of Drosophila larvae to noxious mechanical stimuli. In wild-type larvae, dendrites of nociceptive class IV da neurons intercalate between epidermal cells at apodemes, which function as body wall muscle attachment sites, but not at other sites in the epidermis. From a genetic screen we identified miR-14 as a regulator of dendrite positioning in the epidermis: miR-14 is expressed broadly in the epidermis but not in apodemes, and miR-14 inactivation leads to excessive apical dendrite intercalation between epidermal cells. We found that miR-14 regulates expression and distribution of the epidermal Innexins ogre and Inx2 and that these epidermal gap junction proteins restrict epidermal dendrite intercalation. Finally, we found that altering the extent of epidermal dendrite intercalation had corresponding effects on nociception: increasing epidermal intercalation sensitized larvae to noxious mechanical inputs and increased mechanically evoked calcium responses in nociceptive neurons, whereas reducing epidermal dendrite intercalation had the opposite effects. Altogether, these studies identify epidermal dendrite intercalation as a mechanism for mechanical coupling of nociceptive neurons to the epidermis, with nociceptive sensitivity tuned by the extent of intercalation.
Project description:mRNA expression levels were determined by NGS for wildtype larvae as well as for larvae lacking HP1a [Su(var)205^04/Su(var)205^05 transheterozygotes]. RNA samples from wildtype (OR) and HP1a mutant third instar larvae were examined, using duplicate biological samples and Illumina NGS.
Project description:modENCODE_submission_762 This submission comes from a modENCODE project of Eric Lai. For full list of modENCODE projects, see http://www.genome.gov/26524648 Project Goal: We plan to generate a comprehensive catalog of expressed and functional microRNAs, and generate biological evidence for their regulatory activity. We plan also to delineate the primary transcription units of microRNA genes. Finally, we plan to annotate other classes of non-miRNA expressed small RNAs, as least some of which may define novel classes of small RNA genes. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf EXPERIMENT TYPE: RNA-seq. BIOLOGICAL SOURCE: Strain: Canton-S; Tissue: L1 larvae; Replicate type: biological; Developmental Stage: 1st Instar Larvae; Sex: NA; EXPERIMENTAL FACTORS: Strain: Canton-S
Project description:modENCODE_submission_748 This submission comes from a modENCODE project of Eric Lai. For full list of modENCODE projects, see http://www.genome.gov/26524648 Project Goal: We plan to generate a comprehensive catalog of expressed and functional microRNAs, and generate biological evidence for their regulatory activity. We plan also to delineate the primary transcription units of microRNA genes. Finally, we plan to annotate other classes of non-miRNA expressed small RNAs, as least some of which may define novel classes of small RNA genes. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf EXPERIMENT TYPE: RNA-seq. BIOLOGICAL SOURCE: Strain: Canton-S; Tissue: L3 larvae; Replicate type: biological; Developmental Stage: 3rd Instar Larvae; Sex: NA; EXPERIMENTAL FACTORS: Strain: Canton-S
Project description:Nociceptive neurons develop a complex dendritic arbor to sense noxious stimuli, which enables animals to react to environmental insults and perform self-protective behaviours. The genetic programs controlling neuronal dendritic morphogenesis are poorly understood. In C. elegans, the PVD sensory neuron generates a complex dendritic arbor that envelops the body of the animal. This nociceptive neuron enables study of dendrite formation in vivo. We used expression arrays to identify genes highly enriched in the PVD neuron while undergoing dendritic morphogenesis. These genes could function in pathways controlling dendrite formation. We employ the mRNA-tagging method to isolate poly(A) RNA from the PVD and OLL neurons by expressing a 3X FLAG-tagged poly(A) binding protein PAB-1 in PVD and OLL under control of the ser-2prom3B promoter. The enriched poly(A) RNA is amplified using the NuGEN WT-Pico amplification system and applied to Affymetrix C. elegans gene expression microarrays. A reference sample was obtained by isolating total RNA from whole animals at the L3/L4 stages and processed as above.
Project description:Gene expression levels were determined in 3rd instar and adult Drosophila melanogaster reared during spaceflight, to elucidate the genetic and molecular mechanisms underpinning the effects of microgravity on the immune system. The goal was to validate the Drosophila model for understanding alterations of innate immune responses in humans due to spaceflight. Five containers of flies, with ten female and five male fruit flies in each container, were housed and bred on the space shuttle (average orbit altitude of 330.35 km) for 12 days and 18.5 hours, with a new generation reared in microgravity. RNA was extracted on the day of shuttle landing from whole body animals (3rd instar larvae and adults), hybridized to Drosophila 2.0 Affymetrix genome arrays, and the expression level of all genes was normalized against the gene expression level from the corresponding developmental stage animals raised on ground. Spaceflight altered the expression of larval genes involved in the maturation of plasmatocytes (macrophages) and their phagocytic response, as well as the level of constitutive expression of pattern recognition receptors and opsonins that specifically recognize bacteria, and of lysozymes, antimicrobial peptide pathway and immune stress genes, hallmarks of humoral immunity. Larval microarrays (FL 6 samples) are based on RNA extracted from 6 independent sets of 50 mid 3rd instar larvae reared in microgravity and collected on the day of landing after 12 days and 18.5 hours on the space shuttle and the same number of control larvae raised on ground (GL 6 samples). Adults microarrays (F1 3 samples) are based on RNA from 3 sets of 20 adult females each, that emerged during spaceflight and within 4 hours of landing and the same number of adult females from the corresponding ground control containers (G1 3 samples).
Project description:Drosophila 3rd instar larvae were subjected to septic injury. After 6h plasmatocytes were isolated, fixed and subjected to ChIP-seq.