Project description:Genome-wide transcriptional changes in development provide important insight into mechanisms underlying growth, differentiation, and patterning. However, such large-scale developmental studies have been limited to a few representatives of Ecdysozoans and Chordates. Here, we characterize transcriptomes of embryonic, larval, and metamorphic development in the marine mollusc Aplysia californica and reveal novel molecular components associated with life history transitions. Specifically, we identify more than 20 signal peptides, putative hormones, and transcription factors in association with early development and metamorphic stages-many of which seem to be evolutionarily conserved elements of signal transduction pathways. We also characterize genes related to biomineralization-a critical process of molluscan development. In summary, our experiment provides the first large-scale survey of gene expression in mollusc development, and complements previous studies on the regulatory mechanisms underlying body plan patterning and the formation of larval and juvenile structures. This study serves as a resource for further functional annotation of transcripts and genes in Aplysia, specifically and molluscs in general. A comparison of the Aplysia developmental transcriptome with similar studies in the zebra fish Danio rerio, the fruit fly Drosophila melanogaster, the nematode Caenorhabditis elegans, and other studies on molluscs suggests an overall highly divergent pattern of gene regulatory mechanisms that are likely a consequence of the different developmental modes of these organisms.
Project description:The marine mollusc Aplysia is a well established experimental system for cellular and systems neuroscience because of the relatively simple organization of its nervous system and the presence within it of the largest nerve cells in the animal kingdom, many of which are uniquely identifiable in every member of the species. Until now, molecular analyses of Aplysia have been seriously handicapped by lack of adequate genomic information, with only 200 sequences publicly available when this project was initiated in 2003. By sequencing cDNA libraries from the central nervous system, we have identified over 175,000 ESTs (expressed sequence tags), of which 19,814 are unique neuronal gene products and 9469 has been annotated. Through comparison with the complete genomic data available for Drosophila and C. elegans, we estimate that we have sequence information for approximately 50-70% of the total transcriptome of the Aplysia nervous system. We also identified 9,223 unique gene products in a modulatory serotonergic cell and about 1,000 unique gene products from its processes. Using gene expression oligoarrays constructed using the Aplysia EST database we also have characterized the transcript profile of sensory and motor neurons. In addition to increasing the amount of publicly available gene sequences of Aplysia by two orders of magnitude, this collection of transcripts is distinctive from a comparative biology point of view. It represents the largest database available for any member of the Lophotrochozoa clade of the animal kingdom. These molecular resources should allow the detailed study of the genomics of identified cells and circuits and provide in Aplysia a much needed bridge between genes, behavior, and learning. This SuperSeries is composed of the SubSeries listed below.
Project description:Study objectiveTo characterize sleep in the marine mollusk, Aplysia californica.DesignAnimal behavior and activity were assessed using video recordings to measure activity, resting posture, resting place preference, and behavior after rest deprivation. Latencies for behavioral responses were measured for appetitive and aversive stimuli for animals in the wake and rest states.SettingCircadian research laboratory for Aplysia.Patients or participantsA. californica from the Pacific Ocean.InterventionsN/A.Measurements and resultsAplysia rest almost exclusively during the night in a semi-contracted body position with preferential resting locations in the upper corners of their tank. Resting animals demonstrate longer latencies in head orientation and biting in response to a seaweed stimulus and less frequent escape response steps following an aversive salt stimulus applied to the tail compared to awake animals at the same time point. Aplysia exhibit rebound rest the day following rest deprivation during the night, but not after similar handling stimulation during the day.ConclusionsResting behavior in Aplysia fulfills all invertebrate characteristics of sleep including: (1) a specific sleep body posture, (2) preferred resting location, (3) reversible behavioral quiescence, (4) elevated arousal thresholds for sensory stimuli during sleep, and (5) compensatory sleep rebound after sleep deprivation.
Project description:This study aims at identifying non-coding RNA driving AAA pathogenesis and progression.To fish out AAA-relevant circRNA targets, we took advantage of array technology and profiled differentially expressed circRNAs in AAAs vs. non-AAA human tissue specimens. We then focused on studying circRNA-exerted gene expression regulation at the locus of origin and its implication in AAA disease dynamics.