UPRRP College of Natural Sciences

About: UPRRP College of Natural Sciences is a based out in . It is known for research contribution in the topics: Apoptosis & Population. The organization has 9323 authors who have published 11826 publications receiving 284172 citations.

Multiple-myeloma-related WHSC1/MMSET isoform RE-IIBP is a histone methyltransferase with transcriptional repression activity.

Abstract: Histone methylation is crucial for transcriptional regulation and chromatin remodeling. It has been suggested that the SET domain containing protein RE-IIBP (interleukin-5 [IL-5] response element II binding protein) may perform a function in the carcinogenesis of certain tumor types, including myeloma. However, the pathogenic role of RE-IIBP in these diseases remains to be clearly elucidated. In this study, we have conducted an investigation into the relationship between the histone-methylating activity of RE-IIBP and transcriptional regulation. Here, we report that RE-IIBP is up-regulated in the blood cells of leukemia patients, and we characterized the histone H3 lysine 27 (H3-K27) methyltransferase activity of RE-IIBP. Point mutant analysis revealed that SET domain cysteine 483 and arginine 477 are critical residues for the histone methyltransferase (HMTase) activity of RE-IIBP. RE-IIBP also represses basal transcription via histone deacetylase (HDAC) recruitment, which may be mediated by H3-K27 methylation. In the chromatin immunoprecipitation assays, we showed that RE-IIBP overexpression induces histone H3-K27 methylation, HDAC recruitment, and histone H3 hypoacetylation on the IL-5 promoter and represses expression. Conversely, short hairpin RNA-mediated knockdown of RE-IIBP reduces histone H3-K27 methylation and HDAC occupancy around the IL-5 promoter. These data illustrate the important regulatory role of RE-IIBP in transcriptional regulation, thereby pointing to the important role of HMTase activity in carcinogenesis.

Biodiversity and geochemistry of an extremely acidic, low-temperature subterranean environment sustained by chemolithotrophy.

Abstract: The geochemical dynamics and composition of microbial communities within a low-temperature (�8.5°C), long-abandoned (> 90 years) underground pyrite mine (Cae Coch, located in north Wales) were investigated. Surface water percolating through fractures in the residual pyrite ore body that forms the roof of the mine becomes extremely acidic and iron-enriched due to microbially accelerated oxidative dissolution of the sulfide mineral. Water droplets on the mine roof were found to host a very limited diversity of exclusively autotrophic microorganisms, dominated by the recently described psychrotolerant iron/sulfur-oxidizing acidophile Acidithiobacillus ferrivorans, and smaller numbers of iron-oxidizing Leptospirillum ferrooxidans. In contrast, flowing water within the mine chamber was colonized with vast macroscopic microbial growths, in the form of acid streamers and microbial stalactites, where the dominant microorganisms were Betaproteobacteria (autotrophic iron oxidizers such as �Ferrovum myxofaciens� and a bacterium related to Gallionella ferruginea). An isolated pool within the mine showed some similarity (although greater biodiversity) to the roof droplets, and was the only site where archaea were relatively abundant. Bacteria not previously associated with extremely acidic, metal-rich environments (a Sphingomonas sp. and Ralstonia pickettii) were found within the abandoned mine. Data supported the hypothesis that the Cae Coch ecosystem is underpinned by acidophilic, mostly autotrophic, bacteria that use ferrous iron present in the pyrite ore body as their source of energy, with a limited role for sulfur-based autotrophy. Results of this study highlight the importance of novel bacterial species (At. ferrivorans and acidophilic iron-oxidizing Betaproteobacteria) in mediating mineral oxidation and redox transformations of iron in acidic, low-temperature environments.

Identification of sigma factors for growth phase-related promoter selectivity of RNA polymerases from Streptomyces coelicolor A3(2)

Abstract: We examined the promoter selectivity of RNA polymerase (RNAP) from Streptomyces coelicolor at two growth phases by in vitro transcription. Distinct sets of promoters were preferentially recognized by either exponential or stationary phase RNAP. No change in molecular weight or net charge of the core subunits was observed, suggesting that the associated specificity factors determined phase-specific promoter selectivity of the holoenzyme. Five different specificity factors and their cognate promoters were identified by in vitro holoenzyme reconstitution and transcription assays. sigma66 (sigma hrdB) and sigma46 (sigma hrdD) recognized promoters (rrnD p2 and dagA p4 for sigma66, actII-orf4 p and whiB p2 for sigma46) preferentially transcribed by the exponential phase RNAP. sigma52 recognized promoters (dagA p3 and actIII px1) preferentially transcribed by the stationary phase RNAP. Sigma28 (sigma sigE) recognized promoters (hrdD p1, whiB p1 and dagA p2) transcribed equally by both RNAPs. A novel 31 kDa specificity factor recognized actIII px2, glnR p2 and hrdD p2 promoters preferentially transcribed by the stationary phase RNAP. This factor was isolated from the stationary phase RNAP and reconstituted holoenzyme in vitro as a sigma factor. The N-terminal sequence suggests that it is a novel factor. By examining phase-specific promoter recognition pattern we can predict that holoenzyme Esigma52 and Esigma31 activities are higher in the stationary phase, whereas Esigma66 and Esigma46activities are higher in the exponential phase. Possible promoter sequences recognized by some of these sigma factors were suggested.

Limited proliferation capacity of aortic intima resident macrophages requires monocyte recruitment for atherosclerotic plaque progression.

Abstract: Early atherosclerosis depends upon responses by immune cells resident in the intimal aortic wall. Specifically, the healthy intima is thought to be populated by vascular dendritic cells (DCs) that, during hypercholesterolemia, initiate atherosclerosis by being the first to accumulate cholesterol. Whether these cells remain key players in later stages of disease is unknown. Using murine lineage-tracing models and gene expression profiling, we reveal that myeloid cells present in the intima of the aortic arch are not DCs but instead specialized aortic intima resident macrophages (MacAIR) that depend upon colony-stimulating factor 1 and are sustained by local proliferation. Although MacAIR comprise the earliest foam cells in plaques, their proliferation during plaque progression is limited. After months of hypercholesterolemia, their presence in plaques is overtaken by recruited monocytes, which induce MacAIR-defining genes. These data redefine the lineage of intimal phagocytes and suggest that proliferation is insufficient to sustain generations of macrophages during plaque progression. Williams and colleagues investigate the origin, dynamics and transcriptional profiles of aortic intima macrophages during atherosclerosis disease progression.