Ptf1a-dependent gene expression during pancreas development (TLDA part)
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ABSTRACT: We first used RNA-Seq technology to explore gene expression in mouse Ptf1a^YFP/+ [het] FACS sorted cells at E11.5 (early pancreatic Multipotent Progenitor Cells) and E15.5 (nascent acinar cells) as well as in Ptf1a^YFP/YFP [null] at E11.5 (delayed early MPC): this is deposited with accession number E-MTAB-449. We then examined 376 selected genes identified as differentially expressed between early pancreatic MPC and nascent acinar cells or between early pancreatic and delayed early MPCs by Taqman Low Density Arrays (TLDAs) with Real Time RT-PCR for each 1-day time point from E10.5 to E15. 5 in Ptf1a^YFP/+ [het] and for E10.5 and E11.5 in Ptf1aYFP/YFP [null] . Finally, 94 genes identified in the first phase of TLDAs (including 2 endogenous control, Gapdh and 18S) were analyzed in a second TLDA phase for each 1-day time point from E10.5 to -E18.5 in Ptf1a^YFP/+ [het] and for E11.5 in Ptf1aYFP/YFP [null] with biological replicates (n>=3) for each time point.
Project description:This experiment used RNA-Seq technology to explore gene expression in mouse Ptf1a^YFP/+ [het] FACS sorted cells at E11.5 (early pancreatic Multipotent Progenitor Cells) and E15.5 (nascent acinar cells) as well as in Ptf1a^YFP/YFP [null] at E11.5 (delayed early MPC). 376 selected genes identified as differentially expressed between early pancreatic MPC and nascent acinar cells or between early pancreatic and delayed early MPCs have then been examined by Taqman Low Density Arrays (TLDAs) with Real Time RT-PCR for each 1-day time point from E10.5 to E15. 5 in Ptf1a^YFP/+ [het] and for E10.5 and E11.5 in Ptf1aYFP/YFP [null] . Finally, 94 genes identified in the first phase of TLDAs (including 2 endogenous control, Gapdh and 18S) were analyzed in a second TLDA phase for each 1-day time point from E10.5 to -E18.5 in Ptf1a^YFP/+ [het] and for E11.5 in Ptf1aYFP/YFP [null] with biological replicates (n>=3) for each time point.
Project description:Multipotent pancreatic progenitors (MPC) are defined as Ptf1a+, Mychigh, Cpa+ cells. During the transition from MPC to unipotent acinar progenitors, c-Myc is down-regulated whereas Ptf1a is up-regulated, leading to the deployment of the acinar program. Here, we show that c-Myc and Ptf1a interact directly and c-Myc binds to, and represses, the transcriptional activity of the PTF1 complex in vitro and in vivo. Using Ela1-Myc mice, in which c-Myc is overexpressed in acinar cells starting at E14.5, we find that acinar cells fail to undergo normal maturation at P1 and this is followed by a massive subsequent repression of the acinar programme. Lineage tracing with Ptf1aCreERT2;Rosa26YFP and Ela1-Myc;Ptf1aCreERT2;Rosa26YFP mice receiving TMX at E15.5 and analyzed at E18.5 revealed that c-Myc overexpression is associated with activation of a hepatic programme but not with pancreatic lineage misspecification At 8 weeks, the silencing of the acinar program is associated with increased expression of the PRC2 complex in a c-Myc dependent manner. Genome wide studies show that Ptf1a and c-Myc display partially overlapping chromatin occupancy patterns and DNA binding competition. We conclude that c-Myc down-regulation during development is crucial for the maturation of pre-acinar to acinar cells. c-Myc overexpression may contribute to pancreatic carcinogenesis by restraining cell differentiation and rendering cells susceptible to transformation.
Project description:Multipotent pancreatic progenitors (MPC) are defined as Ptf1a+, Mychigh, Cpa+ cells. During the transition from MPC to unipotent acinar progenitors, c-Myc is down-regulated whereas Ptf1a is up-regulated, leading to the deployment of the acinar program. Here, we show that c-Myc and Ptf1a interact directly and c-Myc binds to, and represses, the transcriptional activity of the PTF1 complex in vitro and in vivo. Using Ela1-Myc mice, in which c-Myc is overexpressed in acinar cells starting at E14.5, we find that acinar cells fail to undergo normal maturation at P1 and this is followed by a massive subsequent repression of the acinar programme. Lineage tracing with Ptf1aCreERT2;Rosa26YFP and Ela1-Myc;Ptf1aCreERT2;Rosa26YFP mice receiving TMX at E15.5 and analyzed at E18.5 revealed that c-Myc overexpression is associated with activation of a hepatic programme but not with pancreatic lineage misspecification At 8 weeks, the silencing of the acinar program is associated with increased expression of the PRC2 complex in a c-Myc dependent manner. Genome wide studies show that Ptf1a and c-Myc display partially overlapping chromatin occupancy patterns and DNA binding competition. We conclude that c-Myc down-regulation during development is crucial for the maturation of pre-acinar to acinar cells. c-Myc overexpression may contribute to pancreatic carcinogenesis by restraining cell differentiation and rendering cells susceptible to transformation.
Project description:Ptf1a was identified as the essential transcription factor which controls pancreatic exocrine enzyme expression. With lineage tracing eperiments Ptf1a was recognized as an important pancreatic progenitor transcription factor and Ptf1a null mice do not develop a pancreas. We used gene expression arrays to determine the global differeences in expression levels when pancreatic progenitor cells are expanding in Ptf1a heterozygote versus null mutants at E10.5. Ptf1a E10.5 dorsal pancreas total RNA from pools of 3 embryos was twice linear amplified and hybridized to Affymetrix GeneChip Mouse Genome 430 2.0 in triplicate for the Ptf1a KO and in duplicate for the Ptf1a heterozygote
Project description:Ptf1a was identified as the essential transcription factor which controls pancreatic exocrine enzyme expression. With lineage tracing eperiments Ptf1a was recognized as an important pancreatic progenitor transcription factor and Ptf1a null mice do not develop a pancreas. We used gene expression arrays to determine the global differeences in expression levels when pancreatic progenitor cells are expanding in Ptf1a heterozygote versus null mutants at E10.5.
Project description:Pancreatic specific transcription factor1a (Ptf1a) immunoprecipitated chromatin from 266.6 cells produced 26 million tags with the Illumina high throughput sequencing technology. Many of the mapped tags were genes which were found to be differentially expressed at E10.5 in the microarray experiments comparing Ptf1a heterozygotes versus null mutant mice (study GSE26816). As Ptf1a is a bHLH transcription factor, it recognizes an E Box on the chromatin CANNTG. Since it belongs to a transcription factor complex, one of which recognizes the binding site TGGGAA, we also found this sequence one, two or three helical turns of DNA away from the E-box where peaks were detected. Ptf1a chromatin immunoprecipitation of cross-linked pancreatic cells, 266.6, to compare with the expressed genes in Ptf1a +/- vs -/- E10.5 pancreatic dorsal buds.
Project description:S23 experiment: We sought to identify the microRNAs (miRNAs) enriched in the neural crest cell (NCC) population from E11.5 mouse embryos. To accomplish this, we utilized a transgenic mouse line harboring Cre-recombinase under the control of the Wnt1 NCC-specific promoter and also carrying the R26R-YFP allele. We sorted YFP+ (NCCs) and YFP- (non-NCCs) from E11.5 Wnt1Cre-R26R mouse embryos via FACS and compared the relative enrichment of miRNAs in the YFP+ population by miRNA microarray. 220 experiment: We sought to identify the microRNAs (miRNAs) enriched in the neural crest cell (NCC) population from E10.5 mouse embryos. To accomplish this, we utilized a transgenic mouse line harboring Cre-recombinase under the control of the Wnt1 NCC-specific promoter and also carrying the R26R-YFP allele. We sorted YFP+ (NCCs) and YFP- (non-NCCs) from E10.5 Wnt1Cre-R26R mouse embryos via FACS and compared the relative enrichment of miRNAs in the YFP+ population by miRNA microarray. 221 experiment: Our research has shown that heterozygous deletion of the miRNA processing enzyme Dicer leads to developmental delay of the thymus in mouse embryos. We sought to identify the microRNAs (miRNAs) affected by the loss of a single copy of Dicer in the neural crest cell (NCC) population from E10.5 mouse embryos. To accomplish this, we utilized a transgenic mouse line harboring a floxed allele of Dicer, Cre-recombinase under the control of the Wnt1 NCC-specific promoter, and also carrying the R26R-YFP allele. We sorted YFP+ (NCCs) cells from E10.5 Dicerfl/+,Wnt1Cre,R26R and Dicer+/+,Wnt1Cre,R26R mouse embryos via FACS and compared the relative expression of miRNAs in the Dicer-heterozygotes compared to Dicer-wildtypes by miRNA microarray. S23 experiment: RNA from YFP+ (NCCs) and YFP- (non-NCCs) cells sorted by FACS from E11.5 Wnt1Cre-R26R mouse embryos was isolated and hybridized to Exiqon miRNA microarrays v10. Cells from five E11.5 embryos were sorted into YFP+ and YFP- populations and pooled. 220 experiment: RNA from YFP+ (NCCs) and YFP- (non-NCCs) cells sorted by FACS from E10.5 Wnt1Cre-R26R mouse embryos was isolated and hybridized to Exiqon miRNA microarrays v10. Cells from ten E10.5 embryos were sorted into YFP+ and YFP- populations and pooled. 221 experiment: RNA from YFP+ (NCCs) cells sorted by FACS from E10.5 Dicerfl/+,Wnt1Cre,R26R and Dicer+/+,Wnt1Cre,R26R mouse embryos was isolated and hybridized to Exiqon miRNA microarrays v10. Cells from ten embryos were sorted into YFP+ populations and pooled for each genotype.
Project description:Significant progress has been made in recent years in characterizing human multipotent progenitor cells (hMPCs) of the early pancreas; however, the identity and persistence of these cells during the second trimester, after the initiation of branching morphogenesis, remain elusive. Additionally, studies on hMPCs have been hindered by few isolation methods that allow for the recovery of live cells. Here, we investigated the tip progenitor domain in the branched epithelium of human fetal pancreas between 13.5 and 17.5 gestational weeks by immunohistological staining. We also used a novel RNA‐based technology to isolate live cells followed by gene expression analyses. We identified cells co‐expressing SOX9 and PTF1A, two transcription factors known to be important for pancreatic MPCs, within the tips of the epithelium and observed a decrease in their proportions over time. Pancreatic SOX9+/PTF1A+ cells were enriched for MPC markers, including MYC and GATA6. These cells were proliferative and appeared active in branching morphogenesis and matrix remodeling, as evidenced by gene set enrichment analysis. We identified a hub of genes pertaining to the expanding tip progenitor niche, such as FOXF1, GLI3, TBX3, FGFR1, TGFBR2, ITGAV, ITGA2, and ITGB3. YAP1 of the Hippo pathway emerged as a highly enriched component within the SOX9+/PTF1A+ cells. Single‐cell RNA‐sequencing further corroborated the findings by identifying a cluster of SOX9+/PTF1A+ cells with multipotent characteristics. Based on these results, we propose that the SOX9+/PTF1A+ cells in the human pancreas are uncommitted MPC‐like cells that reside at the tips of the expanding pancreatic epithelium, directing self‐renewal and inducing pancreatic organogenesis.
Project description:The Ptf1a gene has essential functions during several stages of pancreas development. It is expressed in the naïve endoderm and required pancreas cell fate specification; it is also required later in the differentiation and maintenance of acinar cells. To identify the regulatory genetic program downstream of Ptf1a required for early pancreatic fate acquisition, we used microarrays to perform a comprehensive gene expression analysis of Ptf1a overexpressing endodermal tissue at NF32 and NF36. The results revealed an up-regulation on 1142 probe sets over 2-fold. Additional analyses, by in situ hybridizations, identified 9 genes that were endodermally expressed after the onset of endogenous Ptf1a; STXBP1, putative transmembrane protein TA-2, C25H, IGFBP1, IRF1, HALPN3, Hey1, sestrin 1, syndecan-4. These results provide insight into the regulatory network activated by Ptf1a during early pancreas development.
Project description:S23 experiment: We sought to identify the microRNAs (miRNAs) enriched in the neural crest cell (NCC) population from E11.5 mouse embryos. To accomplish this, we utilized a transgenic mouse line harboring Cre-recombinase under the control of the Wnt1 NCC-specific promoter and also carrying the R26R-YFP allele. We sorted YFP+ (NCCs) and YFP- (non-NCCs) from E11.5 Wnt1Cre-R26R mouse embryos via FACS and compared the relative enrichment of miRNAs in the YFP+ population by miRNA microarray. 220 experiment: We sought to identify the microRNAs (miRNAs) enriched in the neural crest cell (NCC) population from E10.5 mouse embryos. To accomplish this, we utilized a transgenic mouse line harboring Cre-recombinase under the control of the Wnt1 NCC-specific promoter and also carrying the R26R-YFP allele. We sorted YFP+ (NCCs) and YFP- (non-NCCs) from E10.5 Wnt1Cre-R26R mouse embryos via FACS and compared the relative enrichment of miRNAs in the YFP+ population by miRNA microarray. 221 experiment: Our research has shown that heterozygous deletion of the miRNA processing enzyme Dicer leads to developmental delay of the thymus in mouse embryos. We sought to identify the microRNAs (miRNAs) affected by the loss of a single copy of Dicer in the neural crest cell (NCC) population from E10.5 mouse embryos. To accomplish this, we utilized a transgenic mouse line harboring a floxed allele of Dicer, Cre-recombinase under the control of the Wnt1 NCC-specific promoter, and also carrying the R26R-YFP allele. We sorted YFP+ (NCCs) cells from E10.5 Dicerfl/+,Wnt1Cre,R26R and Dicer+/+,Wnt1Cre,R26R mouse embryos via FACS and compared the relative expression of miRNAs in the Dicer-heterozygotes compared to Dicer-wildtypes by miRNA microarray.