Project description:The ERK5 MAP kinase signalling pathway was recently discovered as a driver of naïve pluripotency in mouse Embryonic Stem Cells (mESCs). However, the molecular functions of ERK5 in mESCs have not been investigated. Here, we employ combinatorial mESC proteomics to identify ERK5 target genes and substrates. Global proteomic profiling reveals ZSCAN4 and other 2-cell stage genes as transcriptional targets of the ERK5 pathway. ZSCAN4 expression is specifically induced by ERK5-dependent transcription of the core pluripotency factor KLF2. Additionally, ERK5 directly phosphorylates tandem KLF2 Thr-Pro/Ser-Pro motifs identified by phosphoproteomics to recruit the FBXW7-CUL1 E3 ligase, promoting KLF2 ubiquitylation and degradation. ERK5 phosphorylation of KLF2 thereby provides negative-feedback control to restrain transcriptional induction of ZSCAN4. Our data uncover an auto-regulatory module by which ERK5 co-opts KLF2 to pattern ZSCAN4 expression. This study provides the first molecular insight into ERK5 functions in mESCs, and suggests a novel role for ERK5 signalling in stem cell rejuvenation
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: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.