Project description:The Insm1 gene encodes a zinc finger factor expressed in many endocrine organs. We show here that Insm1 is required for differentiation of all endocrine cell types in the pituitary. Thus, in Insm1 mutant mice, hormones characteristic of the different pituitary cell types (thyroid, follicle and melanocyte stimulating hormone, adrenocorticotrope hormone, growth hormone and prolactin) are absent or produced at markedly reduced levels. The differentiation deficit is accompanied by an up-regulated expression of components of the Notch signaling pathway. Further, skeletal muscle-specific genes are ectopically expressed, indicating that Insm1 blocks a muscle-specific expression program. Since Insm1 is also essential for differentiation of endocrine cells in the pancreas, intestine and adrenal gland, it is emerging as a transcription factor that acts in a pan-endocrine manner. The Insm1 factor contains a SNAG domain at its N-terminus, and we show here that the SNAG domain recruits histone modifying factors (Kdm1a, Hdac1/2 and Rcor1-3) and other proteins implicated in transcriptional regulation (Hmg20a/b and Gse1). Deletion of the SNAG domain in mice disrupted differentiation of pituitary endocrine cells, and resulted in an upregulated expression of components of the Notch signaling pathway and ectopic expression of skeletal muscle-specific genes. Our work demonstrates that Insm1 acts in the transcriptional network that controls differentiation of endocrine cells in the anterior pituitary gland, and requires the SNAG domain to exert this function in vivo. Analysis of genes regulated by Insm1 in embryonic day 17.5 pituitary gland. Total RNA from pituitary glands of E17.5 control embryos was compared to E17.5 Insm1 mutant embryos.
Project description:The Insm1 gene encodes a zinc finger factor expressed in many endocrine organs. We show here that Insm1 is required for differentiation of all endocrine cell types in the pituitary. Thus, in Insm1 mutant mice, hormones characteristic of the different pituitary cell types (thyroid, follicle and melanocyte stimulating hormone, adrenocorticotrope hormone, growth hormone and prolactin) are absent or produced at markedly reduced levels. The differentiation deficit is accompanied by an up-regulated expression of components of the Notch signaling pathway. Further, skeletal muscle-specific genes are ectopically expressed, indicating that Insm1 blocks a muscle-specific expression program. Since Insm1 is also essential for differentiation of endocrine cells in the pancreas, intestine and adrenal gland, it is emerging as a transcription factor that acts in a pan-endocrine manner. The Insm1 factor contains a SNAG domain at its N-terminus, and we show here that the SNAG domain recruits histone modifying factors (Kdm1a, Hdac1/2 and Rcor1-3) and other proteins implicated in transcriptional regulation (Hmg20a/b and Gse1). Deletion of the SNAG domain in mice disrupted differentiation of pituitary endocrine cells, and resulted in an upregulated expression of components of the Notch signaling pathway and ectopic expression of skeletal muscle-specific genes. Our work demonstrates that Insm1 acts in the transcriptional network that controls differentiation of endocrine cells in the anterior pituitary gland, and requires the SNAG domain to exert this function in vivo.
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:We collected whole genome testis expression data from hybrid zone mice. We integrated GWAS mapping of testis expression traits and low testis weight to gain insight into the genetic basis of hybrid male sterility.
Project description:To characterize the genetic basis of hybrid male sterility in detail, we used a systems genetics approach, integrating mapping of gene expression traits with sterility phenotypes and QTL. We measured genome-wide testis expression in 305 male F2s from a cross between wild-derived inbred strains of M. musculus musculus and M. m. domesticus. We identified several thousand cis- and trans-acting QTL contributing to expression variation (eQTL). Many trans eQTL cluster into eleven ‘hotspots,’ seven of which co-localize with QTL for sterility phenotypes identified in the cross. The number and clustering of trans eQTL - but not cis eQTL - were substantially lower when mapping was restricted to a ‘fertile’ subset of mice, providing evidence that trans eQTL hotspots are related to sterility. Functional annotation of transcripts with eQTL provides insights into the biological processes disrupted by sterility loci and guides prioritization of candidate genes. Using a conditional mapping approach, we identified eQTL dependent on interactions between loci, revealing a complex system of epistasis. Our results illuminate established patterns, including the role of the X chromosome in hybrid sterility.
Project description:miR-29a/b1 was reported to be involved in the regulation of reproductive function in female mice, but the underlying molecular mechanisms were not clear. In this study, female mice lacking miR-29a/b1 showed a delay in vaginal opening, irregular estrus cycles, ovulation disorder and infertility. However, the development of egg was normal in mutant mice and the ovulation disorder could be rescued by the superovulation treatment. The plasma level of luteinizing hormone (LH) was significantly lower in the mutant mice. Using iTRAQ coupled with LC-MS/MS, we found that the deficiency of miR-29a/b1 in mice resulted in an abnormal expression of a number of proteins involved in vesicular transport and secretion in the pituitary gland. The miR-29a/b1 targeting gene Dnmt3a and Hdac4 were up-regulated in the pituitary of miR-29a/b1 knockout mice suggesting that these two epigenetic writers may be the upstream causes for these phenotype changes due to miR-29a/b1 deficiency. These findings demonstrated that miR-29a/b1 is indispensable for the function of the reproductive axis through regulating LH secretion in the pituitary gland.
Project description:Genome-wide Insm1 binding sites analysis revealed an overrepresentation of sequences predicted to bind bHLH and/or forkhead factors, and further analyses demonstrated that most Insm1 sites in the genome are co-occupied by Neurod1 and Foxa2. Binding regions co-occupied by all three factors but not single Insm1 sites explained a significant fraction of gene expression changes in Insm1 mutant β-cells. Together, our data provide evidence that an Insm1, Neurod1 and Foxa2 network maintains a mature gene expression program in β-cells. 6 samples include, replicates of Insm1 and Foxa2, IgG pull down as a control
Project description:Insm1, encoding a zinc finger protein, is expressed specifically in neuroendocrine cells. Recent study showed the first evidence of Insm1 expression in medullary thymic epithelial cells (mTEC). Here we investigated the expression and function of Insm1 in mTEC. Mutation of Insm1 resulted in decreased proportion of mTEChi although normal development of other types of thymic cells. We detected altered expression of a subset of tissue-restricted antigens (TRAs) and mild decreased expression of Aire and Fezf2 in Insm1 mutant mTEC. We further showed that Insm1 recognizes a DNA sequence which is similar to the CCCTC-Binding factor (CTCF) binding motif. Mutation of Insm1 altered CTCF binding genome widely and thus the expression of genes. In nude mice transplanted with Insm1 mutant thymus, autoimmune responses were observed in multiple peripheral tissues. In thymus specific Insm1 mutant mice, we detected decreased induction of regulatory T (Treg) cells in the thymus, obvious lymphocytes infiltration and autoimmune antibody reaction in several peripheral tissues. In thymic epithelial cells specific Insm1 overexpression mice, we detected enlarged mTEC proportion and increased expression of mTEC specific genes. Thus, we suggest that Insm1 is a novel regulator of mTEC function and autoimmunity.
Project description:Insm1, encoding a zinc finger protein, is expressed specifically in neuroendocrine cells. Recent study showed the first evidence of Insm1 expression in medullary thymic epithelial cells (mTEC). Here we investigated the expression and function of Insm1 in mTEC. Mutation of Insm1 resulted in decreased proportion of mTEChi although normal development of other types of thymic cells. We detected altered expression of a subset of tissue-restricted antigens (TRAs) and mild decreased expression of Aire and Fezf2 in Insm1 mutant mTEC. We further showed that Insm1 recognizes a DNA sequence which is similar to the CCCTC-Binding factor (CTCF) binding motif. Mutation of Insm1 altered CTCF binding genome widely and thus the expression of genes. In nude mice transplanted with Insm1 mutant thymus, autoimmune responses were observed in multiple peripheral tissues. In thymus specific Insm1 mutant mice, we detected decreased induction of regulatory T (Treg) cells in the thymus, obvious lymphocytes infiltration and autoimmune antibody reaction in several peripheral tissues. In thymic epithelial cells specific Insm1 overexpression mice, we detected enlarged mTEC proportion and increased expression of mTEC specific genes. Thus, we suggest that Insm1 is a novel regulator of mTEC function and autoimmunity.
Project description:Translational research is commonly performed in the C57B6/J mouse strain, chosen for its genetic homogeneity and phenotypic uniformity. Here, we evaluate the suitability of the white-footed deer mouse (Peromyscus leucopus) as a model organism for aging research, offering a comparative analysis against C57B6/J and diversity outbred (DO) Mus musculus strains. Our study includes comparisons of body composition, skeletal muscle function, and cardiovascular parameters, shedding light on potential applications and limitations of P. leucopus in aging studies. Notably, P. leucopus exhibits distinct body composition characteristics, emphasizing reduced muscle force exertion and a unique metabolism, particularly in fat mass. Cardiovascular assessments showed changes in arterial stiffness, challenging conventional assumptions and highlighting the need for a nuanced interpretation of aging-related phenotypes. Our study also highlights inherent challenges associated with maintaining and phenotyping P. leucopus cohorts. Behavioral considerations, including anxiety-induced responses during handling and phenotyping assessment, pose obstacles in acquiring meaningful data. Moreover, the unique anatomy of P. leucopus necessitates careful adaptation of protocols designed for Mus musculus. While showcasing potential benefits, further extensive analyses across broader age ranges and larger cohorts are necessary to establish the reliability of P. leucopus as a robust and translatable model for aging studies.