α4-Integrin deficiency in human CD34 cells engenders precocious erythroid differentiation but inhibits enucleation.

The functional impact of integrin expression in erythropoiesis has been previously emphasized through its decisive influence on erythroid cell-microenvironment (matrix and cellular) interactions, especially under conditions of stress. Beyond that, in several in vitro studies the relationship between the two erythroid integrins, α4 and α5, has been incongruous in terms of a proliferative support, either synergistic or antagonistic, whereas a dominant influence of α4 integrin on terminal erythropoiesis in vitro and in vivo has been consistently emphasized. However, the specific cellular and molecular details of this effect have not been defined, especially for human cells.

Cotargeting among microRNAs in the brain.

MicroRNAs (miRNAs) play roles in diverse developmental and disease processes. Distinct miRNAs have hundreds to thousands of conserved mRNA binding sites but typically direct only modest repression via single sites. Cotargeting of individual mRNAs by different miRNAs could potentially achieve stronger and more complex patterns of repression.

Antagonistic regulation of mRNA expression and splicing by CELF and MBNL proteins.

RNA binding proteins of the conserved CUGBP1, Elav-like factor (CELF) family contribute to heart and skeletal muscle development and are implicated in myotonic dystrophy (DM). To understand their genome-wide functions, we analyzed the transcriptome dynamics following induction of CELF1 or CELF2 in adult mouse heart and of CELF1 in muscle by RNA-seq, complemented by crosslinking/immunoprecipitation-sequencing (CLIP-seq) analysis of mouse cells and tissues to distinguish direct from indirect regulatory targets. We identified hundreds of mRNAs bound in their 3' UTRs by both CELF1 and the developmentally induced MBNL1 protein, a threefold greater overlap in target messages than expected, including messages involved in development and cell differentiation.

Genetic engineering of human pluripotent cells using TALE nucleases.

Targeted genetic engineering of human pluripotent cells is a prerequisite for exploiting their full potential. Such genetic manipulations can be achieved using site-specific nucleases. Here we engineered transcription activator-like effector nucleases (TALENs) for five distinct genomic loci.

Efficient targeted gene disruption in the soma and germ line of the frog Xenopus tropicalis using engineered zinc-finger nucleases.

The frog Xenopus, an important research organism in cell and developmental biology, currently lacks tools for targeted mutagenesis. Here, we address this problem by genome editing with zinc-finger nucleases (ZFNs). ZFNs directed against an eGFP transgene in Xenopus tropicalis induced mutations consistent with nonhomologous end joining at the target site, resulting in mosaic loss of the fluorescence phenotype at high frequencies.