Monitoring endoplasmic reticulum stress responsive mRNAs by RNA sequencing

Gene expression profile upon endoplasmic reticulum (ER) stress was analyzed by deep shotgun sequencing of mRNAs (DSSR) using RNAs from polysomes or cytoplasm of the HT29 cell. Two time points, 4h after tunicamycin treatment when IRE1α signaling pathway is active and 16h after the treatment when it is inactive, were used. There was a transient decrease in the proportion of shorter mRNA species (<1000bp) in polysome, while it increased transiently in the cytoplasm. Despite such an overall change and decrease in total amount of polysomes, the majority of the 6966 genes analyzed had less than 2 fold change in their expressions. We searched for the genes whose expression was elevated by 2 folds or more in both polysome and cytoplasm and confirmed the results with RT-PCR. There were 7 genes elevated only at 4h (Group I), 20 genes only at 16h (Group II) and 7 genes both at 4 and 16h (Group III). There were 3 genes involved in ribosomal RNA biogenesis in Group I and 2 genes involved mTOR control in Group III. This was consistent with the concept that the ribosome is the essential site for managing ER stress. DSSR is a useful tool for the search of candidates of ER stress responsive genes.     

CEF1/CDC5 alleles modulate transitions between catalytic conformations of the spliceosome

Conformational change within the spliceosome is required between the first and second catalytic steps of pre-mRNA splicing. A prior genetic screen for suppressors of an intron mutant that stalls between the two steps yielded both prp8 and non-prp8 alleles that suppressed second-step splicing defects. We have now identified the strongest non-prp8 suppressors as alleles of the NTC (Prp19 complex) component, CEF1. These cef1 alleles generally suppress second-step defects caused by a variety of intron mutations, mutations in U6 snRNA, or deletion of the second-step protein factor Prp17, and they can activate alternative 3' splice sites. Genetic and functional interactions between cef1 and prp8 alleles suggest that they modulate the same event(s) in the first-to-second-step transition, most likely by stabilization of the second-step spliceosome; in contrast, alleles of U6 snRNA that also alter this transition modulate a distinct event, most likely by stabilization of the first-step spliceosome. These results implicate a myb-like domain of Cef1/CDC5 in interactions that modulate conformational states of the spliceosome and suggest that alteration of these events affects splice site use, resulting in alternative splicing-like patterns in yeast.     

Sample-to-SNP kit: A reliable,easy and fast tool for the detection of HFE p.H63D and p.C282Y variations associated to hereditary hemochromatosis

Classical hereditary hemochromatosis involves the HFE-gene and diagnostic analysis of the DNA variants HFE p.C282Y (c.845G > A; rs1800562) and HFE p.H63D (c.187C > G; rs1799945). The affected protein alters the iron homeostasis resulting in iron overload in various tissues. The aim of this study was to validate the TaqMan-based Sample-to-SNP protocol for the analysis of the HFE-p.C282Y and p.H63D variants with regard to accuracy, usefulness and reproducibility compared to an existing SNP protocol. The Sample-to-SNP protocol uses an approach where the DNA template is made accessible from a cell lysate followed by TaqMan analysis. Besides the HFE-SNPs other eight SNPs were used as well. These SNPs were: Coagulation factor II-gene F2 c.20210G > A, Coagulation factor V-gene F5 p.R506Q (c.1517G > A; rs121917732), Mitochondria SNP: mt7028 G > A, Mitochondria SNP: mt12308 A > G, Proprotein convertase subtilisin/kexin type 9-gene PCSK9 p.R46L (c.137G > T), Plutathione S-transferase pi 1-gene GSTP1 p.I105V (c313A > G; rs1695), LXR g.-171 A > G, ZNF202 g.-118 G > T. In conclusion the Sample-to-SNP kit proved to be an accurate, reliable, robust, easy to use and rapid TaqMan-based SNP detection protocol, which could be quickly implemented in a routine diagnostic or research facility.     

The impact of the International Atomic Energy Agency (IAEA) program on radiation and tissue banking in Korea

In 1971, first bone bank was established at the Department of Orthopaedic Surgery in Catholic University of Korea. The first clinical case was reported at the Journal of Korean Orthopaedic Association in 1973. Subsequently, more than 60 surgical bone banks were established in the university and teaching hospitals throughout country. In 1990, the Korea Biomaterial Research Institute (KBRI) organised the IAEA/RCA training course on tissue banking. In this course students from 17 countries participated. In 1994 the first collaboration for cadaver tissue recovery was performed. It is important to single out that the various religious groups in Korea have favourable attitudes towards tissue donation, which contributes to the success of the tissue banking programs in the country. The demands of allograft were getting increased in the Korean medical and dental society. Currently, 62 hospital based bone banks, 5 processing tissue banks, 1 regional tissue bank and more than 30 tissue distributors are working in Korea. Based on the U.S.A. usage of more than 1,000,000 grafts per year, 100,000–200,000 grafts will be needed in Korea. Those findings indicate a greatly increased need for training of tissue bank operators. The Korean society will need at least 20–30 tissue bank operators for training in every year. The National Training Centre (NTC) for tissue bank operators and medical personal using the IAEA Curriculum in the Korean languages was established in 2003. From 2004 to 2006, NTC have been trained 40 tissue bank operators. They have produced at least 10,000 tissues per year. These figures indicate a cost saving of US$ 10 million. Within 5 years, NTC will train 100 tissue bank operators. These individuals and their respective banks will provide an increasing number of high quality grafts to the communities they serve at a cost far less than if they were acquired from abroad.     

Downregulation of Axl in non-MYCN amplified neuroblastoma cell lines reduces migration

Neuroblastomas (NBL) are common pediatric solid tumors with a variable clinical course. At diagnosis half of all neuroblastoma patients presents with metastatic disease. The mechanisms of metastasis are largely unknown. Gene expression profiles (HU133plus2.0 arrays, Affymetrix) of 17 NBL and 5 peripheral neuro-ectodermal cell lines were used to identify a subgroup of non-MYCN amplified (non-NMA) NBL cell lines with a distinct gene expression profile and characterized by high expression of AXL. Axl is a tyrosine kinase receptor which plays a role in the metastatic process of several types of cancer. We hypothesized that Axl contributes to the metastasizing potential of non-NMA NBL and tested if AXL silencing diminishes malignant properties of high Axl expressing cell lines.     

A H NMR study of the specificity of α-l-arabinofuranosidases on natural and unnatural substrates

Background

The detailed characterization of arabinoxylan-active enzymes, such as double-substituted xylan arabinofuranosidase activity, is still a challenging topic. Ad hoc chromogenic substrates are useful tools and can reveal subtle differences in enzymatic behavior. In this study, enzyme selectivity on natural substrates has been compared with enzyme selectivity towards aryl-glycosides. This has proven to be a suitable approach to understand how artificial substrates can be used to characterize arabinoxylan-active α-l-arabinofuranosidases (Abfs).

Methods

Real-time NMR using a range of artificial chromogenic, synthetic pseudo-natural and natural substrates was employed to determine the hydrolytic abilities and specificity of different Abfs.

Results

The way in which synthetic di-arabinofuranosylated substrates are hydrolyzed by Abfs mirrors the behavior of enzymes on natural arabinoxylo-oligosaccharide (AXOS). Family GH43 Abfs that are strictly specific for mono-substituted d-xylosyl moieties (AXH-m) do not hydrolyze synthetic di-arabinofuranosylated substrates, while those specific for di-substituted moieties (AXH-d) remove a single l-arabinofuranosyl (l-Araf) group. GH51 Abfs, which are supposedly AXH-m enzymes, can release l-Araf from disubstituted d-xylosyl moieties, when these are non-reducing terminal groups.

Conclusions and general significance

The present study reveals that although the activity of Abfs on artificial substrates can be quite different from that displayed on natural substrates, enzyme specificity is well conserved. This implies that carefully chosen artificial substrates bearing di-arabinofuranosyl d-xylosyl moieties are convenient tools to probe selectivity in new Abfs. Moreover, this study has further clarified the relative promiscuity of GH51 Abfs, which can apparently hydrolyze terminal disubstitutions in AXOS, albeit less efficiently than mono-substituted motifs.