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: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:Freshwater planarians can be used as a model to investigate neuronal function and maintenance in adults in vivo. We knocked down expression for 2 transcription factors, then sequenced resulting animals to examine transcriptional changes that may have occurred. There are 3 triplicated conditions: control(RNAi) using the unc22 gene from C. elegans, lhx1/5-1(RNAi), and pitx(RNAi). Worms were fed RNAi for each gene 5 times over 12 days then were collected 12 days later. Approximately 50 million single-end reads were performed on each sample.
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:Planarians exhibit extraordinary regenerative abilities driven by pluripotent neoblasts, yet the roles of post-mitotic progenitor and differentiated cells in this process remain incompletely understood. Here, we investigate the function of agat+ cells, epidermal progenitors expressing members of the arginine:glycine amidinotransferase (agat) gene family, in the regeneration of Schmidtea mediterranea. Comprehensive analysis of all five planarian agat paralogs revealed that agat-1, -2, -3, and -4 are co-expressed in subepidermal populations enriched at wound sites, while agat-5 is minimally expressed. RNAi-mediated knockdown of agat-1 and agat-2 resulted in severe defects: agat-1 primarily disrupted tissue homeostasis, whereas agat-2 specifically impaired blastema formation and stem cell maintenance during regeneration. Transcriptional profiling of isolated agat+ cells demonstrated enrichment for metabolic and transport-related genes, including those involved in creatine and ornithine metabolism, as well as secretory pathway components. Functional assays showed that creatine supplementation partially rescued regeneration defects following agat-2 knockdown, implicating creatine and related metabolites as critical factors for regenerative success. These findings redefine agat+ cells as a heterogeneous, metabolically active, and potentially secretory population that supports regeneration beyond their canonical role as transitional progenitors. Our results highlight the importance of differentiated support cells and their metabolic outputs in tissue regeneration, providing new insight into the coordination between progenitor populations and stem cells during whole-body regeneration in planarians.