DUX4-induced dsRNA and MYC mRNA stabilization activate apoptotic pathways in human cell models of facioscapulohumeral dystrophy.

Facioscapulohumeral dystrophy (FSHD) is caused by the mis-expression of DUX4 in skeletal muscle cells. DUX4 is a transcription factor that activates genes normally associated with stem cell biology and its mis-expression in FSHD cells results in apoptosis. To identify genes and pathways necessary for DUX4-mediated apoptosis, we performed an siRNA screen in an RD rhabdomyosarcoma cell line with an inducible DUX4 transgene.

Distinct Activities of Myf5 and MyoD Indicate Separate Roles in Skeletal Muscle Lineage Specification and Differentiation.

Most transcription factor families contain highly related paralogs generated by gene duplication, and functional divergence is generally accomplished by activation of distinct sets of genes by each member. Here we compare the molecular functions of Myf5 and MyoD, two highly related bHLH transcription factors that regulate skeletal muscle specification and differentiation. We find that MyoD and Myf5 bind the same sites genome-wide but have distinct functions: Myf5 induces histone acetylation without Pol II recruitment or robust gene activation, whereas MyoD induces histone acetylation, recruits Pol II, and robustly activates gene transcription.

Polycomb-mediated repression during terminal differentiation: what don't you want to be when you grow up?

Chromatin-modifying enzymes are known to be critical components for the correct differentiation of embryonic stem cells into specific lineages, such as neurons. Recently, the role of Polycomb group proteins has been studied in the specification and differentiation of muscle stem cells. In this perspective, we review a recent study by Juan and colleagues (pp.

Changes in H2A.Z occupancy and DNA methylation during B-cell lymphomagenesis.

The histone variant H2A.Z has been implicated in the regulation of gene expression, and in plants antagonizes DNA methylation. Here, we ask whether a similar relationship exists in mammals, using a mouse B-cell lymphoma model, where chromatin states can be monitored during tumorigenesis.

Insights into the role of DNA methylation in disease through the use of mouse models.

Epigenetics was originally defined as the interaction of genes with their environment that brings the phenotype into being. It now refers to the study of heritable changes in gene expression that occur without a change in DNA sequence. To date, the best understood epigenetic mechanisms are CpG DNA methylation and histone modifications.

Aberrant DNA methylation occurs in colon neoplasms arising in the azoxymethane colon cancer model.

Mouse models of intestinal tumors have advanced our understanding of the role of gene mutations in colorectal malignancy. However, the utility of these systems for studying the role of epigenetic alterations in intestinal neoplasms remains to be defined. Consequently, we assessed the role of aberrant DNA methylation in the azoxymethane (AOM) rodent model of colon cancer.

Induction of cytotoxic T-lymphocyte responses to enhanced green and yellow fluorescent proteins after myeloablative conditioning.

Lentiviral vectors are increasingly being used for transferring genes into hematopoietic stem cells (HSCs) due to their ability to transduce nondividing cells. Whereas results in in vitro studies and the nonobese diabetic/severe combined immunodeficiency (NOD/SCID) model have been highly encouraging, studies in large animals have not confirmed the superior transduction of HSCs using lentiviral vectors versus oncoretroviral vectors. In contrast to the stable gene marking we have consistently achieved with oncoretroviral vectors in animals that received myeloablative conditioning, we observed the complete disappearance of genetically modified enhanced green or yellow fluorescent protein-expressing cells in 5 baboons that received transplants of HSCs transduced with lentiviral vectors alone or in combination with oncoretroviral vectors.