Conventional murine gene targeting

CRISPR/Cas9-Assisted Genome Editing in Murine Embryonic Stem Cells

The study of gene function in normal human physiology and pathophysiology is complicated by countless factors such as genetic diversity (~98 million SNPs identified in the human genome as of June 2015), environmental exposure, epigenetic imprinting, maternal/in utero exposure, diet, exercise, age, sex, socioeconomic factors, and many other variables. Inbred mouse lines have allowed researchers to control for many of the variables that define human diversity but complicate the study of the human genome, gene/protein function, cellular and molecular pathways, and countless other genetic diseases. Furthermore, genetically modified mouse models enable us to generate and study mice whose genomes differ by as little as a single point mutation while controlling for non-genomic variables. This allows researchers to elucidate the quintessential function of a gene, which will further not only our scientific understanding, but provide key insight into human health and disease. Recent advances in CRISPR/Cas9 genome editing have revolutionized scientific protocols for introducing mutations into the mammalian genome. The ensuing chapter provides an overview of CRISPR/Cas9 genome editing in murine embryonic stem cells for the generation of genetically modified mouse models.

Concise Review: Getting to the Core of Inherited Bone Marrow Failures

Bone marrow failure syndromes (BMFS) are a group of disorders with complex pathophysiology characterized by a common phenotype of peripheral cytopenia and/or hypoplastic bone marrow. Understanding genetic factors contributing to the pathophysiology of BMFS has enabled the identification of causative genes and development of diagnostic tests. To date more than 40 mutations in genes involved in maintenance of genomic stability, DNA repair, ribosome and telomere biology have been identified. In addition, pathophysiological studies have provided insights into several biological pathways leading to the characterization of genotype/phenotype correlations as well as the development of diagnostic approaches and management strategies. Recent developments in bone marrow transplant techniques and the choice of conditioning regimens have helped improve transplant outcomes. However, current morbidity and mortality remain unacceptable underlining the need for further research in this area. Studies in mice have largely been unable to mimic disease phenotype in humans due to difficulties in fully replicating the human mutations and the differences between mouse and human cells with regard to telomere length regulation, processing of reactive oxygen species and lifespan. Recent advances in induced pluripotency have provided novel insights into disease pathogenesis and have generated excellent platforms for identifying signaling pathways and functional mapping of haplo‐insufficient genes involved in large‐scale chromosomal deletions–associated disorders. In this review, we have summarized the current state of knowledge in the field of BMFS with specific focus on modeling the inherited forms and how to best utilize these models for the development of targeted therapies. Stem Cells2017;35:284–298