SETD1B mutations confer apoptosis resistance and BCL2 independence in B cell lymphoma.

The translocation t(14;18) activates BCL2 and is considered the initiating genetic lesion in most follicular lymphomas (FL). Surprisingly, FL patients fail to respond to the BCL2 inhibitor, Venetoclax. We show that mutations and deletions affecting the histone lysine methyltransferase SETD1B (KMT2G) occur in 7% of FLs and 16% of diffuse large B cell lymphomas (DLBCL).

Alterations of the Mdm2 C-Terminus Differentially Impact Its Function In Vivo.

Unlabelled: Murine double minute 2 (Mdm2) is the principal E3-ubiquitin ligase for p53 and contains a C2H2C4 type RING domain wherein the last cysteine residue is followed by an evolutionarily conserved 13 amino acid C-terminal tail. Previous studies have indicated that integrity of the C-terminal tail is critical for Mdm2 function. Recently, a mutation extending the MDM2 length by five amino acids was identified and associated with enhanced p53 response in fibroblasts and premature aging in a human patient.

Targeting Bfl-1 via acute CDK9 inhibition overcomes intrinsic BH3-mimetic resistance in lymphomas.

BH3 mimetics like venetoclax target prosurvival Bcl-2 family proteins and are important therapeutics in the treatment of hematological malignancies. We demonstrate that endogenous Bfl-1 expression can render preclinical lymphoma tumor models insensitive to Mcl-1 and Bcl-2 inhibitors. However, suppression of Bfl-1 alone was insufficient to fully induce apoptosis in Bfl-1-expressing lymphomas, highlighting the need for targeting additional prosurvival proteins in this context.

Daxx maintains endogenous retroviral silencing and restricts cellular plasticity in vivo.

Tumor sequencing studies have emphasized the role of epigenetics and altered chromatin homeostasis in cancer. Mutations in , which encodes a chaperone for the histone 3.3 variant, occur in 25% of pancreatic neuroendocrine tumors (PanNETs).

Rapid Evaluation of CRISPR Guides and Donors for Engineering Mice.

Although the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/ CRISPR associated protein 9 (Cas9) technique has dramatically lowered the cost and increased the speed of generating genetically engineered mice, success depends on using guide RNAs and donor DNAs which direct efficient knock-out (KO) or knock-in (KI). By Sanger sequencing DNA from blastocysts previously injected with the same CRISPR components intended to produce the engineered mice, one can test the effectiveness of different guide RNAs and donor DNAs. We describe in detail here a simple, rapid (three days), inexpensive protocol, for amplifying DNA from blastocysts to determine the results of CRISPR point mutation KIs.

Genotyping Genetically Modified (GM) Mice.

Prior to generating a new mouse model, it is important to plan the method that will be used to detect which of the mice generated have the mutation(s) desired. Nearly, all types of mutations may be detected using PCR. However, the choice of primers will differ depending upon the method used to generate the model.

Transient enhancement of p53 activity protects from radiation-induced gastrointestinal toxicity.

Gastrointestinal (GI) syndrome is a serious side effect and dose-limiting toxicity observed in patients undergoing lower-abdominal radiotherapy. Previous mouse studies show that gene dosage determines susceptibility to GI syndrome development. However, the translational relevance of p53 activity has not been addressed.

Dicer1 Phosphomimetic Promotes Tumor Progression and Dissemination.

functions as a tumor suppressor in mouse models. In humans, somatic mutations are associated with many cancers in adults, and patients with DICER1 syndrome with germline mutations are susceptible to childhood cancers. Dicer is phosphorylated by the ERK-MAP kinase pathway and because this pathway is activated in human cancers, we asked whether phosphorylated Dicer1 contributed to tumor development.

Constitutive Dicer1 phosphorylation accelerates metabolism and aging in vivo.

gene alterations and decreased expression are associated with developmental disorders and diseases in humans. Oscillation of Dicer1 phosphorylation and dephosphorylation regulates its function during the oocyte-to-embryo transition in Dicer1 is also phosphorylated upon FGF stimulation at conserved serines in mouse embryonic fibroblasts and HEK293 cells. However, whether phosphorylation of Dicer1 has a role in mammalian development remains unknown.

Loss of digestive organ expansion factor ( reveals an essential role during murine embryonic development that is independent of p53.

Increased levels of inhibitors of the p53 tumor suppressor such as Mdm2 and Mdm4 drive tumor development and thus serve as targets for therapeutic intervention. Recently, digestive organ expansion factor (Diexf) has been identified as a novel inhibitor of p53 in zebrafish. Here, we address the potential role of Diexf as a regulator of the p53 pathway in mammals by generating knockout mice.

Tumorigenesis promotes Mdm4-S overexpression.

Disruption of the p53 tumor suppressor pathway is a primary cause of tumorigenesis. In addition to mutation of the p53 gene itself, overexpression of major negative regulators of p53, MDM2 and MDM4, also act as drivers for tumor development. Recent studies suggest that expression of splice variants of Mdm2 and Mdm4 may be similarly involved in tumor development.

The p53 inhibitor Mdm4 cooperates with multiple genetic lesions in tumourigenesis.

The p53 inhibitor Mdm4 is present at high levels in multiple human cancers. Overexpression of Mdm4 in mice drives the spontaneous development of mostly lymphomas and sarcomas. In this study, we explored the ability of Mdm4 to cooperate with lesions in tumour development.