Cyclic stretch increases splicing noise rate in cultured human fibroblasts

BACKGROUND: Mechanical forces are known to alter the expression of genes, but it has so far not been reported whether they may influence the fidelity of nucleus-based processes. One experimental approach permitting to address this question is the application of cyclic stretch to cultured human fibroblasts. As a marker for the precision of nucleus-based processes, the number of errors that occur during co-transcriptional splicing can then be measured. This so-called splicing noise is found at low frequency in pre-mRNA splicing. FINDINGS: The amount of splicing noise was measured by RT-qPCR of seven exon skips from the test genes AATF, MAP3K11, NF1, PCGF2, POLR2A and RABAC1. In cells treated by altered uniaxial cyclic stretching for 18 h, a uniform and significant increase of splicing noise was found for all detectable exon skips. CONCLUSION: Our data demonstrate that application of cyclic stretch to cultured fibroblasts correlates with a reduced transcriptional fidelity caused by increasing splicing noise

Carbon Fluxes Across Boundaries in the Pacific Arctic Region in a Changing Environment

While the inflow of dissolved inorganic carbon (DIC) from the Pacific Ocean is relatively well quantified, the intermittent input from the East Siberian Sea (ESS) is not. The export flux to the Atlantic Ocean has unknown uncertainty due to a paucity of DIC data from the Canadian Archipelago. Within the region, the Chukchi Sea is the dominant site for atmospheric carbon dioxide (CO2) uptake, while the Beaufort Sea and the Canadian Archipelago take-up much less CO2 with latter potentially a weak source of CO2 during certain times of the year. Additionally, the ESS shelf is a net source of CO2. Summertime CO2 uptake capacity in the deep Canada Basin has increased greatly recently as sea-ice retreat progresses rapidly. The region appears to export more DIC than it receives by a small amount, suggesting that it is probably weakly net heterotrophic. In addition to labile organic carbon (OC) produced in the productive marginal seas, some riverine and coastal erosion-derived OC likely is also recycled. As warming progresses, the Arctic Ocean may produce and export more DIC. Whether this change will turn the Arctic Ocean into a weaker CO2 sink or even a CO2 source for the atmosphere is uncertain and dependent on multiple factors that control the rate of surface water CO2 increase versus the rate of the atmospheric CO2 increase