bcl-2 mRNA contains an AU-rich element (ARE) that functions in regulating bcl-2 stability. Our earlier studies indicated that taxol-or okadaic acid-induced bcl-2 mRNA destabilization in HL-60 cells is associated with decreased binding of trans-acting factors to the ARE. To identify factors that play a role in the regulation of bcl-2 mRNA stability, bcl-2 ARE-binding proteins were purified from HL-60 cells. Three polypeptides of 100, 70, and 32 kDa were isolated from a bcl-2 ARE affinity matrix. Matrix-assisted laser desorption ionization mass spectroscopy analysis identified these proteins as full-length nucleolin and proteolytic fragments of nucleolin. RNA gel shifts assays indicated that recombinant nucleolin (residues 284 -707) binds specifically to bcl-2 ARE RNA. In addition, recombinant nucleolin decreases the rate of decay of mRNA in HL-60 cell extracts in an ARE-dependent manner. Taxol or okadaic acid treatment of HL-60 cells results in proteolysis of nucleolin in a similar time frame as drug-induced bcl-2 mRNA down-regulation. These findings suggest that nucleolin functions as a bcl-2-stabilizing factor and that taxol and okadaic acid treatment induces apoptosis in HL-60 cells through a process that involves down-regulation of nucleolin and destabilization of bcl-2 mRNA.

The antiapoptotic Bcl-2 protein is overexpressed in a variety of cancers, particularly leukemias. In some cell types this is the result of enhanced stability of bcl-2 mRNA, which is controlled by elements in its 3-untranslated region. Nucleolin is one of the proteins that binds to bcl-2 mRNA, thereby increasing its halflife. Here, we examined the site on the bcl-2 3-untranslated region that is bound by nucleolin as well as the protein binding domains important for bcl-2 mRNA recognition. RNase footprinting and RNA fragment binding assays demonstrated that nucleolin binds to a 40-nucleotide region at the 5 end of the 136-nucleotide bcl-2 AU-rich element (ARE bcl-2 ). The first two RNA binding domains of nucleolin were sufficient for high affinity binding to ARE bcl-2 . In RNA decay assays, ARE bcl-2 transcripts were protected from exosomal decay by the addition of nucleolin. AUF1 has been shown to recruit the exosome to mRNAs. When MV-4-11 cell extracts were immunodepleted of AUF1, the rate of decay of ARE bcl-2 transcripts was reduced, indicating that nucleolin and AUF1 have opposing roles in bcl-2 mRNA turnover. When the function of nucleolin in MV-4-11 cells was impaired by treatment with the nucleolin-targeting aptamer AS1411, association of AUF1 with bcl-2 mRNA was increased. This suggests that the degradation of bcl-2 mRNA induced by AS1411 results from both interference with nucleolin protection of bcl-2 mRNA and recruitment of the exosome by AUF1. Based on our findings, we propose a model that illustrates the opposing roles of nucleolin and AUF1 in regulating bcl-2 mRNA stability.Bcl-2, the prototype for its family, is an antiapoptotic protein. Its overexpression has been implicated in multiple cancers and associated with resistance to chemotherapy, making it an important prognostic factor, particularly in hematological malignancies. The Bcl-2 protein is often highly expressed in chronic lymphocytic leukemia (CLL), 5 even though there is no evidence of gene rearrangements that are known to up-regulate bcl-2 transcription. Recently, Otake et al.(1) reported that Bcl-2 overexpression in CLL is related to bcl-2 mRNA stabilization.It is becoming increasingly clear that mRNA stability is an important control point in the regulation of gene expression. In mammalian cells, regulation of mRNA turnover can dramatically alter the abundance of a particular mRNA without changes in transcription. One of the best characterized regulatory elements present in the 3Ј-untranslated region (3Ј-UTR) of mRNAs is the AU-rich element (ARE) (for a review, see Ref.2). These elements are usually composed of AUUUA sequences embedded in a U-rich stretch, and they act as potent mRNA-destabilizing sequences, targeting mRNAs for rapid decay. The bcl-2 mRNA contains an ARE in the 3Ј-UTR that plays a role in regulating its stability (3, 4). The ARE bcl-2 is a sequence of 136 nucleotides (nucleotides 921-1057) just downstream from the stop codon, containing two AUUUA pentamers and a UUAUUUAUU nonamer, which has also been shown to destabili...

Land suitability potential evaluation is an important step to detect the environmental limit in sustainable land use planning. It deals with the assessment of land performances for the specific use that is crop production. In the present study, a land suitability evaluation in a watershed has been carried out through close examination of the indicators of land suitability. The parameters taken into consideration were soil texture, organic matter content, soil depth, slope and land use/land cover. Satellite images of the study area have been classified for land use/ land cover map preparation, while toposheet and ancillary data have been used for slope maps and soil properties determination. An integrated land suitability potential (LSP) index was computed considering the contribution of various parameters of land suitability. The watershed was categorized as good, fair, moderate, average, poor and not suitable by adopting the logical criteria. These categories were arrived at by integrating the various layers with corresponding weights in a geographical information system (GIS). The study demonstrates that a watershed can be categorized into spatially distributed agriculture potential zones based on the soil properties, terrain characteristics and analysing present land use.

Overexpression of the proto-oncogene bcl-2 promotes abnormal cell survival by inhibiting apoptosis. Expression of bcl-2 is determined, in part, by regulatory mechanisms that control the stability of bcl-2 mRNA. Elements in the 3′-untranslated region of bcl-2 mRNA have been shown to play a role in regulating the stability of the message. Previously, it was found that the RNA binding proteins nucleolin and Ebp1 have a role in stabilizing bcl-2 mRNA in HL60 cells. Here, we have identified HuR as a component of bcl-2 messenger ribonucleoprotein (mRNP) complexes.

All-trans retinoic acid (ATRA) induces differentiation of promyelocytic leukemia cells, but the mechanisms by which cellular differentiation leads to apoptosis are not well understood. Studies were done to address the question whether ATRAinduced apoptosis is a consequence of destabilization of bcl-2 mRNA and decreased cellular levels of the anti-apoptotic protein, bcl-2. ATRA induced differentiation of HL-60 cells along the granulocytic pathway within 48 h. The half-lives of bcl-2 mRNA in HL-60 cells incubated with ATRA for 48 or 72 h were reduced to 39 and 7% of the corresponding untreated control values, respectively. Cellular differentiation was accompanied by down-regulation of the cytoplasmic levels of nucleolin, a bcl-2 mRNA-stabilizing protein. Binding of a bcl-2 mRNA instability element (AU-rich element-1) to nucleolin in S100 extracts from ATRA-treated cells was decreased to 15% of control within 72 h. The decay of 5Ј capped, polyadenylated bcl-2 mRNA transcripts containing ARE-1 was more rapid in S100 extracts from ATRA-treated cells compared with untreated cells. However, when recombinant nucleolin was added to extracts of ATRA-treated cells, the rate of bcl-2 mRNA decay was similar to the rate in extracts of untreated cells. These results provide evidence that ATRA-induced apoptosis is a consequence of cellular differentiation, which leads to nucleolin down-regulation and bcl-2 mRNA instability.

The current study presents an algorithm to retrieve surface Soil Moisture (SM) from multi-temporal Synthetic Aperture Radar (SAR) data. The developed algorithm is based on the Cumulative Density Function (CDF) transformation of multi-temporal RADARSAT-2 backscatter coefficient (BC) to obtain relative SM values, and then converts relative SM values into absolute SM values using soil information. The algorithm is tested in a semi-arid tropical region in South India using 30 satellite images of RADARSAT-2, SMOS L2 SM products, and 1262 SM field measurements in 50 plots spanning over 4 years. The validation with the field data showed the ability of the developed algorithm to retrieve SM with RMSE ranging from 0.02 to 0. and a correlation coefficient of approximately 0.9. The developed model is compared and found to be better than the change detection and delta index model. The approach does not require calibration of any parameter to obtain relative SM and hence can easily be extended to any region having time series of SAR data available.Remote Sens. 2015, 7 8129

Microgrid with integrated photo-voltaics (PV) and battery storage system (BSS) is a promising technology for future residential applications. Optimally sizing the PV system and BSS can maximise self-sufficiency, grid relief, and at the same time can be cost-effective by exploiting tariff incentives. To that end, this paper presents a comprehensive optimisation model for the sizing of PV, battery, and grid converter for a microgrid system considering multiple objectives like energy autonomy, power autonomy, payback period, and capital costs. The proposed approach involves developing a holistic technoeconomic microgrid model based on variables like PV system power, azimuth angle, battery size, converter ratings, capital investment and electricity tariffs. The proposed method is applied to determine the optimum capacity of a PV system and BSS for two case residential load profiles in the Netherlands and Texas, US to investigate the effect of meteorological conditions on the relative size of PV and battery. Based on the optimisation results, thumb rules for optimal system sizing are derived to facilitate microgrid design engineers during the initial design phase.

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