Project description:Intracellular trafficking is essential for proper cell signaling. In the pancreas, secretory cells rely on trafficking to regulate blood glucose and digestion. Pancreatic disorders reflect defects in function or development, evoking considerable interest in understanding the molecular genetics governing pancreatic organogenesis. Here, we show the transcription factor NFIA regulates trafficking in both the embryonic and adult pancreas, affecting both developmental cell fate decisions and adult physiology. NFIA deletion from pancreatic progenitors led to the development of more acinar cells and ducts and fewer endocrine cells, whereas ectopic NFIA promoted endocrine formation. We found that NFIA’s effects on trafficking influence endocrine/exocrine cell fate decisions through regulation of Notch. Adult NFIA-deficient mice develop diabetic phenotypes due to impaired insulin granule trafficking and defects in acinar zymogen secretion. This study shows how a single transcription factor, NFIA, thus exerts profound effects on both embryonic cell fate and adult physiology by regulating vesicle trafficking.
Project description:When co-activated with IKKβ, estrogen receptor regulates a subset of genes in invasive cells, which are associated with proliferation, vesicle and intracellular trafficking. These genes are associated with poor survival in patients and are enriched in metastatic tumors in PDX models.
Project description:Although early developmental processes involve cell fate decisions that define the body axes and establish progenitor cell pools, development does not cease once cells are specified. Instead, most cells undergo specific maturation events where changes in the cell transcriptome ensure that the proper gene products are expressed to carry out unique physiological functions. Pancreatic acinar cells mature post-natally to handle an extensive protein synthetic load, establsih organized apical-basal polarity for zymogen granule trafficking, and assemble gap-junctions to perimt efficient cell-cell communication. Despite significant progress in defining transcriptional networks that control initial acinar cell specification and differentiation decisions, little is know regarding the role of transcription factors in the specification and maintenance of maturation events. One candidate maturation effector is MIST1, a secretory cell-restricted transcription factor that has been implicated in controlling regulated exocytosis events in a number of cell types. Embryonic knock-out of MIST1 generates acinar cells that fail to establish an apical-basal organization, fail to properly localize zymogen granule and fail to communicate intra-cellularly, making the exocrine organ highly suceptible to pancreatic diseases. In an effort to identify the gene expression differences responsible for MIST1 regulating mature acinar properties. We generated a tamoxifen-inducible mouse model where MIST1 expression could be activated in vivoand performed gene expression arrays on wildtype, MIST1-null, and induced MIST1 pancreatic RNA. RNA was isolated from pancreata of 8 week old mice using the Qiagen RNeasy Midi kit. Pancreta of wildtype, MIST1-null, and MIST1-null with a tamoxifen inducible MIST1-expressing transgene were harvested 36 hours post-tamoxifen administration. Therefore, this experiment provides information on steady-state gene expression differences between wildtype and MIST1-null mice as well as immediate gene expression changes induced by MIST1 expression.
Project description:Although early developmental processes involve cell fate decisions that define the body axes and establish progenitor cell pools, development does not cease once cells are specified. Instead, most cells undergo specific maturation events where changes in the cell transcriptome ensure that the proper gene products are expressed to carry out unique physiological functions. Pancreatic acinar cells mature post-natally to handle an extensive protein synthetic load, establsih organized apical-basal polarity for zymogen granule trafficking, and assemble gap-junctions to perimt efficient cell-cell communication. Despite significant progress in defining transcriptional networks that control initial acinar cell specification and differentiation decisions, little is know regarding the role of transcription factors in the specification and maintenance of maturation events. One candidate maturation effector is MIST1, a secretory cell-restricted transcription factor that has been implicated in controlling regulated exocytosis events in a number of cell types. Embryonic knock-out of MIST1 generates acinar cells that fail to establish an apical-basal organization, fail to properly localize zymogen granule and fail to communicate intra-cellularly, making the exocrine organ highly suceptible to pancreatic diseases. In an effort to identify the gene expression differences responsible for MIST1 regulating mature acinar properties. We generated a tamoxifen-inducible mouse model where MIST1 expression could be activated in vivoand performed gene expression arrays on wildtype, MIST1-null, and induced MIST1 pancreatic RNA.
Project description:The goal of this study is to profile NFIA DNA-binding properties in the adult mouse brain. We performed chromatin immunoprecipitation of NFIA in the hippocampus and olfactory bulb of wildtype mice, and samples were subjected to sequencing. We find that NFIA preferentially binds DNA in the hippocampus but not in the olfactory bulb as evidenced by the distinct lack of NFIA binding peaks in the olfactory bulb. Mass spectrometry results suggested that NFIA has a significantly higher binding affinity for NFIB in the olfactory bulb, potentially blocking NFIA’s ability to bind DNA. Virally induced siRNAs against NFIB or scramble were injected into the olfactory bulb of adult wildtype mice to knock down NFIB. We performed chromatin immunoprecipitation of NFIA in the olfactory bulb injected with siRNA-NFIB or siRNA-scramble. Subsequent sequencing revealed an increase of NFIA binding in the olfactory bulb upon the depletion of NFIB as compared to the siRNA-scramble and wildtype controls.
Project description:The goal of this study is to determine how the loss of the transcription factor NFIA affects the molecular profiles of adult astrocytes from four brain regions. We performed RNA-sequencing on control and NFIA knockout (KO) astrocytes from the olfactory bulb, hippocampus, cortex, and brainstem, and analyzed the molecular signatures of NFIA KO astrocytes compared to control in each brain region.
Project description:The transcription factor nuclear factor I-A (NFIA) is a regulator of brown adipocyte differentiation. Here we show that the C-terminal 17 amino acid residues of NFIA (which we named pro#3 domain) is required for transcriptional activity of NFIA. Full-length NFIA, but not deletion mutant lacking pro#3 domain rescued impaired Pparg expression and adipogenesis in NFIA-knockout cells. Mechanistically, the ability of NFIA to increase chromatin accessibility is mediated through pro#3 domain. However, the deletion mutant still binds to Myod1 enhancer to decrease chromatin accessibility and represses Myod1 as well as proximally transcribed non-coding RNA called DRReRNA, leading to suppression of myogenic gene program. Therefore, the negative effect of NFIA on myogenic gene program is, at least in part, independent from the positive effect on Pparg expression and its downstream adipogenic gene program. These results uncover multiple ways of action of NFIA to ensure optimal regulation of brown adipocyte differentiation.