Project description:In the mouse neocortex, neural progenitor cells generate neurons through repeated rounds of asymmetric cell division. How distinct fates are established in their daughter cells is unclear. We show here that the TRIM-NHL protein TRIM32 segregates asymmetrically during progenitor division and induces neuronal differentiation in one of the two daughter cells. TRIM32 is highly expressed in differentiating neurons. In both horizontally and vertically dividing progenitor cells, TRIM32 distribution becomes polarized in mitosis so that the protein is enriched in one of the two daughter cells. While TRIM32 overexpression induces cell cycle exit and neuronal differentiation, TRIM32 RNAi causes both daughter cells to proliferate and prevents the initiation of a neuronal differentiation program . TRIM32 ubiquitinates and degrades the transcription factor c-Myc but also binds Argonaute-1 and thereby increases the activity of specific micro-RNAs. We show that Let-7 is one of the TRIM32 targets and is required and sufficient for neuronal differentiation. Our data suggest that the asymmetric segregation of a micro RNA regulator controls self renewal in the mammalian brain. Experiment Overall Design: small RNA from total mouse brain, Ago-1 and TRIM32 IPs were cloned and sequenced using 454 GS FLX system.
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from seven Mus musculus tissues (Heart, Brain, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
Project description:In the mouse neocortex, neural progenitor cells generate neurons through repeated rounds of asymmetric cell division. How distinct fates are established in their daughter cells is unclear. We show here that the TRIM-NHL protein TRIM32 segregates asymmetrically during progenitor division and induces neuronal differentiation in one of the two daughter cells. TRIM32 is highly expressed in differentiating neurons. In both horizontally and vertically dividing progenitor cells, TRIM32 distribution becomes polarized in mitosis so that the protein is enriched in one of the two daughter cells. While TRIM32 overexpression induces cell cycle exit and neuronal differentiation, TRIM32 RNAi causes both daughter cells to proliferate and prevents the initiation of a neuronal differentiation program . TRIM32 ubiquitinates and degrades the transcription factor c-Myc but also binds Argonaute-1 and thereby increases the activity of specific micro-RNAs. We show that Let-7 is one of the TRIM32 targets and is required and sufficient for neuronal differentiation. Our data suggest that the asymmetric segregation of a micro RNA regulator controls self renewal in the mammalian brain.
Project description:Small RNAs are emerging as important molecules for cross-species communication. Thanks to available and affordable sequencing technologies it is now possible to sequence small RNAs (sRNA-Seq) present in samples of interacting organisms. A first step when analyzing sRNA-Seq of two interacting species is to determine which sequences are being produced by which organism. Due to their small size (18-30), small RNAs could easily map to both host and parasite genomes. Here we produced data for Mus musculus intestinal epithelial cells treated with Extracellular Vesicles (EV) produced by the parasitic nematode Heligmosomoides bakeri.