TAZ (WWTR1), identified as a 14-3-3 binding protein with a PDZ binding motif, modulates mesenchymal stem cell differentiation. We now show that TAZ plays a critical role in the migration, invasion, and tumorigenesis of breast cancer cells. TAZ is conspicuously expressed in human breast cancer cell lines in which its expression levels generally correlate with the invasiveness of cancer cells. Overexpression of TAZ in lowexpressing MCF10A cells causes morphologic changes characteristic of cell transformation and promotes cell migration and invasion. Conversely, RNA interference-mediated knockdown of TAZ expression in MCF7 and Hs578T cells reduces cell migration and invasion. TAZ knockdown in MCF7 cells also retards anchorage-independent growth in soft agar and tumorigenesis in nude mice. Significantly, TAZ is overexpressed in f20% of breast cancer samples. These results indicate that TAZ plays a role in the migration, invasion, and tumorigenesis of breast cancer cells and thus presents a novel target for the detection and treatment of breast cancer.

Motile cilia induce fluid movement through their rhythmic beating activity. In mammals, the transcription factor Foxj1 has been implicated in motile cilia formation. Here we show that a zebrafish Foxj1 homolog, foxj1a, is a target of Hedgehog signaling in the floor plate. Loss of Foxj1a compromises the assembly of motile cilia that decorate floor plate cells. Besides the floor plate, foxj1a is expressed in Kupffer's vesicle and pronephric ducts, where it also promotes ciliary differentiation. We show that Foxj1a activates a constellation of genes essential for motile cilia formation and function, and that its activity is sufficient for ectopic development of cilia that resemble motile cilia. We also document that a paralogous gene, foxj1b, is expressed in the otic vesicle and seems to regulate motile cilia formation in this tissue. Our findings identify a dedicated master regulatory role for Foxj1 in the transcriptional program that controls the production of motile cilia.

The thermogenic activity of brown adipose tissue (BAT), important for adaptive thermogenesis and energy expenditure, is mediated by the mitochondrial uncoupling protein1 (Ucp1) that uncouples ATP generation and dissipates the energy as heat. We show here that Cidea, a protein of unknown function sharing sequence similarity with the N-terminal region of DNA fragmentation factors Dffb and Dffa, is expressed at high levels in BAT. Cidea-null mice had higher metabolic rate, lipolysis in BAT and core body temperature when subjected to cold treatment. Notably, Cidea-null mice are lean and resistant to diet-induced obesity and diabetes. Furthermore, we provide evidence that the role of Cidea in regulating thermogenesis, lipolysis and obesity may be mediated in part through its direct suppression of Ucp1 activity. Our data thus indicate a role for Cidea in regulating energy balance and adiposity.

Wwtr1 is a widely expressed 14-3-3-binding protein that regulates the activity of several transcription factors involved in development and disease. To elucidate the physiological role of Wwtr1, we generated Wwtr1 ؊/؊ mice by homologous recombination. Surprisingly, although Wwtr1 is known to regulate the activity of Cbfa1, a transcription factor important for bone development, Wwtr1 ؊/؊ mice show only minor skeletal defects. However, Wwtr1 ؊/؊ animals present with renal cysts that lead to end-stage renal disease. Cysts predominantly originate from the dilation of Bowman's spaces and atrophy of glomerular tufts, reminiscent of glomerulocystic kidney disease in humans. A smaller fraction of cysts is derived from tubules, in particular the collecting duct (CD). The corticomedullary accumulation of cysts also shows similarities with nephronophthisis. Cells lining the cysts carry fewer and shorter cilia and the expression of several genes associated with glomerulocystic kidney disease (Ofd1 and Tsc1) or encoding proteins involved in cilia structure and/or function (Tg737, Kif3a, and Dctn5) is decreased in Wwtr1 ؊/؊ kidneys. The loss of cilia integrity and the down-regulation of Dctn5, Kif3a, Pkhd1 and Ofd1 mRNA expression can be recapitulated in a renal CD epithelial cell line, mIMCD3, by reducing Wwtr1 protein levels using siRNA. Thus, Wwtr1 is critical for the integrity of renal cilia and its absence in mice leads to the development of renal cysts, indicating that Wwtr1 may represent a candidate gene for polycystic kidney disease in humans.bone ͉ cilia ͉ cysts ͉ glomerulus ͉ gene expression