Oncogenic c-Myc induces replication stress by increasing cohesins chromatin occupancy in a CTCF-dependent manner.

Oncogene-induced replication stress is a crucial driver of genomic instability and one of the key events contributing to the onset and evolution of cancer. Despite its critical role in cancer, the mechanisms that generate oncogene-induced replication stress remain not fully understood. Here, we report that an oncogenic c-Myc-dependent increase in cohesins on DNA contributes to the induction of replication stress.

LAMP2 regulates autophagy in the thymic epithelium and thymic stroma-dependent CD4 T cell development.

Within the thymus, thymic epithelial cells (TECs) provide dedicated thymic stroma microenvironments for T cell development. Because TEC functionality is sensitive to aging and cytoablative therapies, unraveling the molecular elements that coordinate their thymopoietic role has fundamental and clinical implications. Particularly, the selection of CD4 T cells depends on interactions between TCRs expressed on T cell precursors and self-peptides:MHC II complexes presented by cortical TECs (cTECs).

CRISPR-Cas9-Mediated Genomic Deletions Protocol in Zebrafish.

Since its first application for site-directed mutagenesis, the CRISPR-Cas9 system has revolutionized genome engineering. Here, we present a validated workflow for the generation of targeted genomic deletions in zebrafish, including the design, cloning, and synthesis of single-guide RNAs and Cas9 mRNA, followed by microinjection in zebrafish embryos and subsequent genotype screening for the establishment of a mutant line. The versatility and efficiency of this pipeline makes the generation of zebrafish models a widely used approach in functional genetics.

In Vivo Reporter Assays Uncover Changes in Enhancer Activity Caused by Type 2 Diabetes-Associated Single Nucleotide Polymorphisms.

Many single nucleotide polymorphisms (SNPs) associated with type 2 diabetes overlap with putative endocrine pancreatic enhancers, suggesting that these SNPs modulate enhancer activity and, consequently, gene expression. We performed in vivo mosaic transgenesis assays in zebrafish to quantitatively test the enhancer activity of type 2 diabetes-associated loci. Six out of 10 tested sequences are endocrine pancreatic enhancers.

Temporal autoregulation during human PU.1 locus SubTAD formation.

Epigenetic control of gene expression occurs within discrete spatial chromosomal units called topologically associating domains (TADs), but the exact spatial requirements of most genes are unknown; this is of particular interest for genes involved in cancer. We therefore applied high-resolution chromosomal conformation capture sequencing to map the three-dimensional (3D) organization of the human locus encoding the key myeloid transcription factor PU.1 in healthy monocytes and acute myeloid leukemia (AML) cells.

Thymic epithelial cells require p53 to support their long-term function in thymopoiesis in mice.

Thymic epithelial cells (TECs) provide crucial microenvironments for T-cell development and tolerance induction. As the regular function of the thymus declines with age, it is of fundamental and clinical relevance to decipher new determinants that control TEC homeostasis in vivo. Beyond its recognized tumor suppressive function, p53 controls several immunoregulatory pathways.

c-MYC oncoprotein dictates transcriptional profiles of ATP-binding cassette transporter genes in chronic myelogenous leukemia CD34+ hematopoietic progenitor cells.

Resistance to chemotherapeutic agents remains one of the major impediments to a successful treatment of chronic myeloid leukemia (CML). Misregulation of the activity of a specific group of ATP-binding cassette transporters (ABC) is responsible for reducing the intracellular concentration of drugs in leukemic cells. Moreover, a consistent body of evidence also suggests that ABC transporters play a role in cancer progression beyond the efflux of cytotoxic drugs.

Two distinct auto-regulatory loops operate at the PU.1 locus in B cells and myeloid cells.

The transcription factor PU.1 occupies a central role in controlling myeloid and early B-cell development, and its correct lineage-specific expression is critical for the differentiation choice of hematopoietic progenitors. However, little is known of how this tissue-specific pattern is established.