Project description:Transcriptional profiling of Schmidtea mediterranea planarians that have been subjected to 2 weeks of runt-1 or control RNAi, amputated and RNA was directly collected at 5min, 9h, and 24h, or neoblasts (X1) were isolated from 9h wounded animals and subsequently RNA was extracted Two-color experiment, 3 replicates per condition (including 10 animals/replica)
Project description:Transcriptional profiling of Schmidtea mediterranea planarians that have been subjected to 2 weeks of runt-1 or control RNAi, amputated and RNA was directly collected at 5min, 9h, and 24h, or neoblasts (X1) were isolated from 9h wounded animals and subsequently RNA was extracted
Project description:Background: Freshwater planarians are well known for their regenerative abilities. Less well known is how planarians maintain spatial patterning in long-lived adult animals or how they re-pattern tissues during regeneration. HOX genes are good candidates to regulate planarian spatial patterning, yet the full complement or genomic clustering of planarian HOX genes has not yet been described, primarily because only a few have been detectable by in situ hybridization, and none have given morphological phenotypes when knocked down by RNAi. Results: Because the planarian Schmidtea mediterranea (S. med) is unsegmented, appendage-less, and morphologically simple, it has been proposed that it may have a simplified HOX gene complement. Here we argue against this hypothesis and show that S. med has a total of 13 HOX genes, which represent homologs to all major axial categories, and can be detected by whole-mount in situ hybridization using a highly-sensitive method. In addition, we show that planarian HOX genes do not cluster in the genome, yet 5/13 have retained aspects of axially-restricted expression. Finally, we confirm HOX gene axial expression by RNA-deep-sequencing 6 anterior-to-posterior “zones” of the animal, which we provide as a dataset to the community to discover other axially-restricted transcripts. Conclusions: Freshwater planarians have an unappreciated HOX gene complexity, with all major axial categories represented. However, we conclude based on adult expression patterns that planarians have a derived body plan and their asexual lifestyle may have allowed for large changes in HOX expression from the last common ancestor between arthropods, flatworms, and vertebrates. Using our in situ method and axial zone RNAseq data, it should be possible to further understand the pathways that pattern the anterior-posterior axis of adult planarians.
Project description:Combining the exposure to the human carcinogen cadmium to in silico and proteomic top-down approaches the conserved function of two novel tumor suppressor genes in planarians were disclosed.
