Epistasis of Transcriptomes Reveals Synergism between Transcriptional Activators Hnf1α and Hnf4α

The transcription of individual genes is determined by combinatorial interactions between DNA–binding transcription factors. The current challenge is to understand how such combinatorial interactions regulate broad genetic programs that underlie cellular functions and disease. The transcription factors Hnf1α and Hnf4α control pancreatic islet β-cell function and growth, and mutations in their genes cause closely related forms of diabetes. We have now exploited genetic epistasis to examine how Hnf1α and Hnf4α functionally interact in pancreatic islets. Expression profiling in islets from either Hnf1a+/− or pancreas-specific Hnf4a mutant mice showed that the two transcription factors regulate a strikingly similar set of genes. We integrated expression and genomic binding studies and show that the shared transcriptional phenotype of these two mutant models is linked to common direct targets, rather than to known effects of Hnf1α on Hnf4a gene transcription. Epistasis analysis with transcriptomes of single- and double-mutant islets revealed that Hnf1α and Hnf4α regulate common targets synergistically. Hnf1α binding in Hnf4a-deficient islets was decreased in selected targets, but remained unaltered in others, thus suggesting that the mechanisms for synergistic regulation are gene-specific. These findings provide an in vivo strategy to study combinatorial gene regulation and reveal how Hnf1α and Hnf4α control a common islet-cell regulatory program that is defective in human monogenic diabetes

Identification of simple sequence repeat markers for sweetpotato weevil resistance

The development of sweetpotato [Ipomoea batatas (L.) Lam] germplasm with resistance to sweetpotato weevil (SPW) requires an understanding of the biochemical and genetic mechanisms of resistance to optimize crop resistance. The African sweetpotato landrace, ‘New Kawogo’, was reported to be moderately resistant to two species of SPW, Cylas puncticollis and Cylas brunneus. Resistance has been associated with the presence of hydroxycinnamic acids esters (HCAs), but the underlying genetic basis remains unknown. To determine the genetic basis of this resistance, a bi-parental sweetpotato population from a cross between the moderately resistant, white-fleshed ‘New Kawogo’ and the highly susceptible, orange-fleshed North American variety ‘Beauregard’ was evaluated for SPW resistance and genotyped with simple sequence repeat (SSR) markers to identify weevil resistance loci. SPW resistance was measured on the basis of field storage root SPW damage severity and total HCA ester concentrations. Moderate broad sense heritability (H2 = 0.49) was observed for weevil resistance in the population. Mean genotype SPW severity scores ranged from 1.0 to 9.0 and 25 progeny exhibited transgressive segregation for SPW resistance. Mean genotype total HCA ester concentrations were significantly different (P < 0.0001). A weak but significant correlation (r = 0.103, P = 0.015) was observed between total HCA ester concentration and SPW severity. A total of five and seven SSR markers were associated with field SPW severity and total HCA ester concentration, respectively. Markers IBS11, IbE5 and IbJ544b showed significant association with both field and HCA-based resistance, representing potential markers for the development of SPW resistant sweetpotato cultivars

Emotional Crowdsourcing Tool Design for Product Development: A Case Study Using Local Crowds

Crowdsourcing is a useful tool for new product development and business innovation. To maximize its utility, regarding a crowdsourcing tool as an everyday thing used by crowds, in this paper, we integrate emotion and emotional design into a human-centred design process with local crowds and showcase an emotional crowdsourcing platform (tool) design for product development. In order to transform emotional design principles into the emotional crowdsourcing tool design, making it useful, usable and pleasurable, we first prototype a suitable emotion/emotional design process, and then identify a set of emotions and corresponding design features applicable for a crowdsourcing platform design and gain better understanding of common key concerns affecting the users’ satisfaction of a platform. Finally, we identify a set of operational toolkits with emotional design features

No evidence for root-mediated allelopathy in Centaurea solstitialis, a species in a commonly allelopathic genus

Phytotoxicity bioassays and pot experiments using activated carbon both suggest that Centaurea solstitialis (yellow star-thistle) does not rely on phytotoxic root exudates for invasion of California grasslands. Pot experiments in which five native species were grown in the presence/absence of C. solstitialis and in the presence/absence of activated carbon (fully crossed design) showed that C. solstitialis competitively suppressed native species, but did not inhibit them through allelochemicals. In separate experiments examining the role of root exudates in invasion success, treatment with crude root exudates and chloroform-extracted root exudates from C. solstitialis reduced growth of the model plant Arabidopsis thaliana. However, high concentrations of the exudates (50%, v/v or 500 μg mL-1) were required to inhibit A. thaliana growth and did not result in A. thaliana mortality, suggesting the presence of only a weak growth inhibitor. Moreover, high concentrations of C. solstitialis crude root exudates did not affect the growth of five native grass species often displaced by C. solstitialis invasions in California grasslands. Finally, root exudates collected from C. solstitialis had weaker effects on a native California root parasite, Triphysaria versicolor, than root exudates collected from Zea mays, a species not renowned for its competitive or invasive capabilities. Our results suggest that, while C. solstitialis might possibly "be persuaded to yield a product that is toxic to one species or another" (Population biology of plants, Academic, 1977), we find no evidence that allelopathic root exudates play a role in the competitive success of this invasive.Fil: Qin, Bo. Colorado State University; Estados UnidosFil: Lau, Jennifer A.. University of California; Estados UnidosFil: Kopshever, Joseph. University of California; Estados UnidosFil: Callaway, Ragan M.. University of Montana; Estados UnidosFil: McGray, Heather. University of California; Estados UnidosFil: Perry, Laura G.. Colorado State University; Estados UnidosFil: Weir, Tiffany L.. Colorado State University; Estados UnidosFil: Paschke, Mark W.. Colorado State University; Estados UnidosFil: Hierro, Jose Luis. University of Montana; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; ArgentinaFil: Yoder, John. University of California; Estados UnidosFil: Vivanco, Jorge M.. Colorado State University; Estados UnidosFil: Strauss, Sharon. University of California; Estados Unido