Rbfox-regulated alternative splicing is critical for zebrafish cardiac and skeletal muscle functions.

Rbfox RNA binding proteins are implicated as regulators of phylogenetically-conserved alternative splicing events important for muscle function. To investigate the function of rbfox genes, we used morpholino-mediated knockdown of muscle-expressed rbfox1l and rbfox2 in zebrafish embryos. Single and double morphant embryos exhibited changes in splicing of overlapping sets of bioinformatically-predicted rbfox target exons, many of which exhibit a muscle-enriched splicing pattern that is conserved in vertebrates.

Vasa and nanos are coexpressed in somatic and germ line tissue from early embryonic cleavage stages through adulthood in the polychaete Capitella sp. I.

Members of the vasa and nanos gene families are involved in germ line development in a number of diverse animals. As a polychaete annelid model for studies of the germ line, Capitella sp. I has several advantages including the presence of dedicated gonads, individuals that reproduce multiple times, and the presence of males, females, and hermaphrodites.

Characterization of twist and snail gene expression during mesoderm and nervous system development in the polychaete annelid Capitella sp. I.

To investigate the evolutionary history of mesoderm in the bilaterian lineage, we are studying mesoderm development in the polychaete annelid, Capitella sp. I, a representative lophotrochozoan. In this study, we focus on the Twist and Snail families as candidate mesodermal patterning genes and report the isolation and in situ expression patterns of two twist homologs (CapI-twt1 and CapI-twt2) and two snail homologs (CapI-sna1 and CapI-sna2) in Capitella sp.

tortuga refines Notch pathway gene expression in the zebrafish presomitic mesoderm at the post-transcriptional level.

We have identified the zebrafish tortuga (tor) gene by an ENU-induced mutation that disrupts the presomitic mesoderm (PSM) expression of Notch pathway genes. In tor mutants, Notch pathway gene expression persists in regions of the PSM where expression is normally off in wild type embryos. The expression of hairy/Enhancer of split-related 1 (her1) is affected first, followed by the delta genes deltaC and deltaD, and finally, by another hairy/Enhancer of split-related gene, her7.

Two linked hairy/Enhancer of split-related zebrafish genes, her1 and her7, function together to refine alternating somite boundaries.

The formation of somites, reiterated structures that will give rise to vertebrae and muscles, is thought to be dependent upon a molecular oscillator that may involve the Notch pathway. hairy/Enhancer of split related [E(spl)]-related (her or hes) genes, potential targets of Notch signaling, have been implicated as an output of the molecular oscillator. We have isolated a zebrafish deficiency, b567, that deletes two linked her genes, her1 and her7.