Heritable differences in gene expression are caused by mutations in DNA sequences encoding cis-regulatory elements and trans-regulatory factors. These two classes of regulatory change differ in their relative contributions to expression differences in natural populations because of the combined effects of mutation and natural selection. Here, we investigate how new mutations create the regulatory variation upon which natural selection acts by quantifying the frequencies and effects of hundreds of new cis- and trans-acting mutations altering activity of the TDH3 promoter in the yeast Saccharomyces cerevisiae in the absence of natural selection. We find that cis-regulatory mutations have larger effects on expression than trans-regulatory mutations and that while trans-regulatory mutations are more common overall, cis- and trans-regulatory changes in expression are equally abundant when only the largest changes in expression are considered. In addition, we find that cis-regulatory mutations are skewed toward decreased expression while trans-regulatory mutations are skewed toward increased expression. We also measure the effects of cis- and trans-regulatory mutations on the variability in gene expression among genetically identical cells, a property of gene expression known as expression noise, finding that trans-regulatory mutations are much more likely to decrease expression noise than cis-regulatory mutations. Because new mutations are the raw material upon which natural selection acts, these differences in the frequencies and effects of cis- and trans-regulatory mutations should be considered in models of regulatory evolution.

This study describes a method of gene delivery to pancreatic islets of adult, living animals by ultrasound targeted microbubble destruction (UTMD). The technique involves incorporation of plasmids into the phospholipid shell of gas-filled microbubbles, which are then infused into rats and destroyed within the pancreatic microcirculation with ultrasound. Specific delivery of genes to islet beta cells by UTMD was achieved by using a plasmid containing a rat insulin 1 promoter (RIP), and reporter gene expression was regulated appropriately by glucose in animals that received a RIP-luciferase plasmid. To demonstrate biological efficacy, we used UTMD to deliver RIP-human insulin and RIP-hexokinase I plasmids to islets of adult rats. Delivery of the former plasmid resulted in clear increases in circulating human C-peptide and decreased blood glucose levels, whereas delivery of the latter plasmid resulted in a clear increase in hexokinase I protein expression in islets, increased insulin levels in blood, and decreased circulating glucose levels. We conclude that UTMD allows relatively noninvasive delivery of genes to pancreatic islets with an efficiency sufficient to modulate beta cell function in adult animals.diabetes ͉ gene therapy ͉ ultrasound

No abstract

Cotton is an economically important crop throughout the world, and is a pioneer crop in salt stress tolerance research. Investigation of the genetic regulation of salinity tolerance will provide information for salt stress-resistant breeding. Here, we employed next-generation RNA-Seq technology to elucidate the salt-tolerant mechanisms in cotton using the diploid cotton species Gossypium davidsonii which has superior stress tolerance. A total of 4744 and 5337 differentially expressed genes (DEGs) were found to be involved in salt stress tolerance in roots and leaves, respectively. Gene function annotation elucidated salt overly sensitive (SOS) and reactive oxygen species (ROS) signaling pathways. Furthermore, we found that photosynthesis pathways and metabolism play important roles in ion homeostasis and oxidation balance. Moreover, our studies revealed that alternative splicing also contributes to salt-stress responses at the posttranscriptional level, implying its functional role in response to salinity stress. This study not only provides a valuable resource for understanding the genetic control of salt stress in cotton, but also lays a substantial foundation for the genetic improvement of crop resistance to salt stress.

The soluble poly(methyl methacrylate-co-octavinyl-polyhedral oligomeric silsesquioxane) (PMMA-POSS) hybrid nanocomposites with improved T g and high thermal stability were synthesized by common free radical polymerization and characterized using FTIR, high-resolution 1 H NMR, 29 Si NMR, GPC, DSC, and TGA. The POSS contents in the nanocomposites were determined based on FTIR spectrum, revealing that it can be effectively adjusted by varying the feed ratio of POSS in the hybrid composites. On the basis of the 1 H NMR analysis, the number of the reacted vinyl groups on each POSS molecules was determined to be about 6-8. The DSC and TGA measurements indicated that the hybrid nanocomposites had higher T g and better thermal properties than the pure PMMA homopolymer. The T g increase mechanism was investigated using FTIR, displaying that the dipole-dipole interaction between PMMA and POSS also plays very important role to the T g improvement besides the molecular motion hindrance from the hybrid structure. The thermal stability enhances with increase of POSS content, which is mainly attributed to the incorporation of nanoscale inorganic POSS uniformly dispersed at molecular level.

No abstract

A series of poly(acetoxystyrene-co-octavinyl-polyhedral oligomeric silsesquioxane) (PAS−POSS) hybrid nanocomposites were synthesized by free radical polymerization and characterized by FTIR, 1H NMR, GPC, DSC, and TGA technologies. The POSS contents in these nanocomposites were calculated on the basis of FTIR data. The results show that POSS content can be controlled by varying the POSS feed ratios. DSC and TGA measurements reveal that the incorporation of POSS into polymers can improve the thermal properties of polymeric materials. The FTIR spectra were employed to explain the T g improvement mechanism. POSS moieties influence the T g of nanocomposite in two ways. At relatively low POSS contents, POSS plays a role of inert diluent to reduce T g. With the increase of POSS contents, both the aggregation of POSS nanoparticles and the dipole−dipole interaction between POSS and PAS molecules contribute to the increase of T g.

Myocardial angiogenesis mediated by human vascular endothelial growth factor 165 (hVEGF 165 ) cDNA was promoted in rat myocardium using an in vivo-targeted gene delivery system known as ultrasound-targeted microbubble destruction (UTMD). Microbubbles carrying plasmids encoding hVEGF 165 , or control solutions were infused intravenously during ultrasonic destruction of the microbubbles within the myocardium. Biochemical and histological assessment of gene expression and angiogenesis were performed 5, 10, and 30 days after UTMD. UTMD-treated myocardium contained hVEGF 165 protein and mRNA. The myocardium of UTMD-treated animals showed hypercellular foci associated with hVEGF 165 expression and endothelial cell markers. Capillary density in UTMD-treated rats increased 18% at 5 days and 33% at 10 days, returning to control levels at 30 days (Po0.0001). Similarly, arteriolar density increased 22% at 5 days, 86% at 10 days, and 31% at 30 days (Po0.0001). Thus, noninvasive delivery of hVEGF 165 to rat myocardium by UTMD resulted in significant increases in myocardial capillary and arteriolar density.