Project description:Thyroid Transcription Factor-1 (TTF-1) is a key regulator of thyroid development and function. In order to identify the genes whose expression depends on TTF-1 transcriptional activity within the thyrocyte we analyzed the consequence of the functional inactivation of this factor in PCCl3 cells. The expression of a fusion protein composed of the DNA binding domain of TTF-1 and of the strong repressive domain of the Engrailed protein (Engr HD) resulted in a dramatic loss of epithelial cell morphology and in proliferation arrest. These changes were reversed when the inhibition of endogenous TTF-1 was relieved. No change was observed when a similar fusion protein containing point mutations abolishing DNA binding activity (Engr HDm) was produced in the cells.
Project description:A chromosomal translocation results in production of an oncogenic PAX8-PPARG fusion protein (PPFP) in a subset of thyroid carcinomas. PAX8 is an important thyroid transcription factor, and PPARG is a transcription factor that plays important roles in the biology of adipocytes and macrophages, but has no known function in the thyroid. PPFP retains the DNA binding domains of both proteins. However, the genomic DNA binding sites of PPFP have not been identified, and only limited data exist to characterize gene expression in PPFP thyroid carcinomas. Therefore, we expressed PPFP in PCCL3 rat thyroid cells and used ChIP-seq to identify PPFP genomic binding sites (PPFP peaks) and RNA-seq to characterize PPFP-dependent gene expression. The genome contains ~20 000 PPFP peaks, including known PAX8 and PPARG binding sites, indicating that both DNA binding domains are functional. PPFP binds to and regulates many genes involved in cancer-related processes such as development and cell division. PPFP also binds to and regulates many genes related to mitochondria and lipid metabolism that are regulated by PPARG in adipocytes. Our data highlight the complexity of PPFP as a transcription factor and the numerous ways that it regulates thyroid oncogenesis.
Project description:Comparison of cistromes from PAX8, NKX2.1, and FOXE1 ChIP-Seq analysis using mouse thyroid gland and rat thyrocyte PCCl3 cells revealed that there is a significant overlap between GLIS3 binding regions and those of PAX8, NKX2.1, and FOXE1 in genes associated with thyroid hormone biosynthesis.
Project description:Analysis of PAX8 binding sites by chromatin immunoprecipitation coupled with ultra-high-throughput sequencing (ChIP-seq) in PCCL3 rat cells. Results provide insight into the contribution of this regulatory factor to transcription genome-wide. We generate a genome wide map of PAX8 binding sites in PCCL3 cells using as negative control an input DNA obtained just prior to Pax8 immunoprecipitation
Project description:Few studies have assessed the patterns of parasite populations of rodents over a longitudinal gradient in Chile. In this work, the gastrointestinal helminthic fauna of invasive rodents in Chile was examined to assess the association between their presence/absence and abundance with latitude, host sex, and host body condition, and to assess the coexistence and correlation of the abundance between parasite species. Rodents were obtained from 20 localities between 33 and 43°S. Helminths were extracted from the gastrointestinal tract and identified morphologically. Overall, 13 helminth taxa were obtained. The most frequently identified parasite species was Heterakis spumosa, and the most abundant was Syphacia muris, while Physaloptera sp. was the most widely distributed. No locality presented with a coexistence that was different from that expected by chance, while the abundance of five helminthic species correlated with the abundance of another in at least one locality, most likely due to co-infection rather than interaction. Host sex was associated with parasite presence or abundance, and female sex-biased parasitism was notably observed in all cases. Body condition and latitude presented either a positive or negative association with the presence or abundance of parasites depending on the species. It is notable that the likely native Physaloptera sp. is widely distributed among invasive rodents. Further, gravid females were found, suggesting spillback of this species to the native fauna. The low frequency and abundance of highly zoonotic hymenolepid species suggest that rodents are of low concern regarding gastrointestinal zoonotic helminths.