Profiling and Identification of Small rDNA-Derived RNAs and Their Potential Biological Functions

Small non-coding RNAs constitute a large family of regulatory molecules with diverse functions. Notably, some small non-coding RNAs matched to rDNA have been identified as qiRNAs and small guide RNAs involved in various biological processes. However, a large number of small rDNA-derived RNAs (srRNAs) are usually neglected and yet to be investigated. We systematically investigated srRNAs using small RNA datasets generated by high-throughput sequencing, and found srRNAs are mainly mapped to rRNA coding regions in sense direction. The datasets from immunoprecipitation and high-throughput sequencing demonstrate that srRNAs are co-immunoprecipitated with Argonaute (AGO) proteins. Furthermore, the srRNA expression profile in mouse liver is affected by diabetes. Overexpression or inhibition of srRNAs in cultured cells shows that srRNAs are involved in various signaling pathways. This study presents a global view of srRNAs in total small RNA and AGO protein complex from different species, and demonstrates that srRNAs are correlated with diabetes, and involved in some biological processes. These findings provide new insights into srRNAs and their functions in various physiological and pathological processes.     

Different haplotypes for cystic fibrosis-linked DNA polymorphisms in Polish and Dutch populations

Summary We analyzed DNA from 34 Polish and 63 Dutch cystic fibrosis (CF) patients and their families using the polymorphic markers XV2c and KM19, which are in linkage disequilibrium with the CF mutation. Strong linkage disequilibrium was found in the Dutch population sample, but the haplotypes of the Polish chromosomes showed a significantly less extreme disequilibrium. Our data and previous studies indicate that the highest degree of homogeneity of the CF defect and hence the best possible use of the XV2c/KM19/CF linkage disequilibrium for CF carrier detection/exclusion is in populations of northern European origin.     

Whisker Movements Reveal Spatial Attention: A Unified Computational Model of Active Sensing Control in the Rat

Spatial attention is most often investigated in the visual modality through measurement of eye movements, with primates, including humans, a widely-studied model. Its study in laboratory rodents, such as mice and rats, requires different techniques, owing to the lack of a visual fovea and the particular ethological relevance of orienting movements of the snout and the whiskers in these animals. In recent years, several reliable relationships have been observed between environmental and behavioural variables and movements of the whiskers, but the function of these responses, as well as how they integrate, remains unclear. Here, we propose a unifying abstract model of whisker movement control that has as its key variable the region of space that is the animal''s current focus of attention, and demonstrate, using computer-simulated behavioral experiments, that the model is consistent with a broad range of experimental observations. A core hypothesis is that the rat explicitly decodes the location in space of whisker contacts and that this representation is used to regulate whisker drive signals. This proposition stands in contrast to earlier proposals that the modulation of whisker movement during exploration is mediated primarily by reflex loops. We go on to argue that the superior colliculus is a candidate neural substrate for the siting of a head-centred map guiding whisker movement, in analogy to current models of visual attention. The proposed model has the potential to offer a more complete understanding of whisker control as well as to highlight the potential of the rodent and its whiskers as a tool for the study of mammalian attention.     

Synergism of interleukin 7 with the thymocyte growth factors interleukin 2, interleukin 6, and tumor necrosis factor alpha in the induction of thymocyte proliferation

The role of previously defined thymocyte (Thm) growth factors in interleukin (IL)-7-induced Thm growth has not been fully elucidated. Therefore, experiments were designed to examine the capacity of IL-7 to: (i) directly induce Thm proliferation in the absence of experimental and known physiologic costimulators of Thm mitogenesis, and (ii) synergize with other Thm growth factors in supporting Thm proliferation. The data indicate that IL-7 is directly mitogenic for Thm; that is, IL-7 induces Thm proliferation in the absence of experimental comitogens such as concanavalin A, phytohemagglutinin, and phorbol myristate acetate and in the presence of neutralizing antibodies to murine IL-1 alpha, IL-1 beta, IL-2, IL-2 receptor (IL-2R)(p55), IL-2R(p70), IL-4, IL-6, and tumor necrosis factor (TNF). We also tested previously described Thm growth factors, i.e., IL-2, IL-4, IL-6, and TNF-alpha, for the capacity to synergize with IL-7 in Thm growth. Our results indicate that IL-2, IL-6, and TNF-alpha, but not IL-4, synergize with IL-7 in supporting Thm proliferation. These data suggest that IL-7 functions alone and in a synergistic fashion with other cytokines to regulate Thm growth.