The 5′-AT-rich half-site of Maf recognition element: a functional target for bZIP transcription factor Maf

The Maf family of proteins are a subgroup of basic region-leucine zipper (bZIP) transcription factors, which recognize a long palindromic DNA sequence [TGCTGAC(G)TCAGCA] known as the Maf recognition element (MARE). Interestingly, the functional target enhancer sequences present in the αA-crystallin gene contain a well-conserved half-site of MARE rather than the entire palindromic sequence. To resolve how Maf proteins bind to target sequences containing only MARE half-sites, we examined their binding activities using electrophoretic gel mobility shift assays as well as in vitro and in vivo reporter assays. Our results indicate that the 5′-flanking region of the MARE half-site is required for Maf proteins to bind both in vitro and in vivo. The critical 5′-flanking sequences for c-Maf were determined by a selection and amplification binding assay and show a preference for AT-rich nucleotides. Furthermore, sequence analysis of the regulatory regions of several target genes also suggests that AT-rich sequences are important. We conclude that Maf can bind to at least two types of target sequences, the classical MARE (palindrome type) and a 5′-AT-rich MARE half-site (half-site type). Our results provide important new insights into the DNA binding and site selection by bZIP transcription factors

Measurement of C-14 Age by Accelerator Mass Spectrometry

加速器質量分析法（AMS）を利用することによりC-14年代測定は大きく飛躍した。従来のβ線計数法にくらべ，炭素試料の必要量は約千分の一となり，測定時間も短縮でき，さらに測定可能な年代も5万年以上までさかのぼることができるようになった。 東京大学原子力研究総合センターのタンデム加速器を用いた東京大学AMSシステムの特長は，「内部ビームモニタ一法」で，14Cを測定すると同時に13Cを測定し，精度の高い測定を可能にしている。ここでは，C-14測定システムの仕組みとC-14年代値を決定する方法を解説する。このC14測定システムの精度，再現性は±1%以下であり，測定限界は67,000年BPと世界最高水準にある。また，測定試料は無定形炭素のかたちで約2～3mgと極微量でよいが，それだけに現代炭素の汚染に十分注意しなくてはならない。木片・木炭などの植物組織や泥炭，貝殻だけでなく，炭素含有量の小さい骨・歯や岩石・鉱物，水・氷などの試料についても，それぞれの試料形態に応じた化学処理法により，微量でも炭素を取り出すことができるので，14Cの測定が可能である。 一方，AMSによるC-14年代測定法によって鉄器の製造年代を推定する方法を開発した。製錬する際に鉄の中に取り込まれた炭素を分離する化学処理法を考案し，C-14年代値を測定した。さび片だけでも測定できることが明らかになったことから，貴重な鉄資料を測定できる可能性が開けた。 しかし得られたC-14年代を暦年代に置き換えるには，いくつかの問題がある。C-14年代値の意味と提案されている補正方法を正確に理解して，適切に年代値を扱う必要がある。An accelerator mass spectrometry (AMS) technique is great tool to determine the radiocarbon age. In an AMS system of Tokyo Univ., the internal beam monitor method provides the precision measurement of 14C/12C. The beam current of 13C is simultaneously measured after acceleration by Faraday cup, while 14C ions are counted. The reproducibility of our system has been improved to be about ±0.8% (1σ). A required amount of sample is reduced to about 0.2 mg and measurable limit of radiocarbon age goes up to 67,000 years. On the contrary, the sample preparation is somewhat troublesome, because of a fairly small quantity. Archaeological samples for dating may be contaminated by 14C in several stages. Then sample preparation for AMS is, at the same time, treatment to eliminate the contaminant. The method and the extent of treatment depend on the type, quality and quantity of the sample. Generally, AAA treatment method is adopted to wood and charcoal. It consists of three steps; Acid extraction, Alkaline extraction and Acid treatment. Appropriate treatments are applied for other kinds of samples; peat, cloth, bone, tooth and shell. Iron ware is the unique sample for measurement of radiocarbon age. When iron was refined, carbon in the fuel was incorporated into iron. The carbon is taken out from the iron sample for the age determination. There are problems to convert the radiocarbon age to the calendar age. It is necessary to take into accounts the half life of 14C and the variation in atomospheric radiocarbon concentration. The latter depends on geomagnetism and the variation during last 10,000 years was measured. Some correction methods are proposed.departmental bulletin pape

High purity NaI(Tl) scintillator to search for dark matter

A high purity and large volume NaI(Tl) scintillator was developed to search for cosmic dark matter. The required densities of radioactive impurities (RIs) such as U-chain, Th-chain are less than a few ppt to establish high sensitivity to dark matter. The impurity of RIs were effectively reduced by selecting raw materials of crucible and by performing chemical reduction of lead ion in NaI raw powder. The impurity of $^{226}$Ra was reduced less than 100 $\mu$Bq/kg in NaI(Tl) crystal. It should be remarked that the impurity of $^{210}$Pb, which is difficult to reduce, is effectively reduced by chemical processing of NaI raw powder down to less than 30 $\mu$Bq/kg. The expected sensitivity to cosmic dark matter by using 250 kg of the high purity and large volume NaI(Tl) scintillator (PICO-LON; Pure Inorganic Crystal Observatory for LOw-background Neutr(al)ino) is 7$\times$10$^{-45}$ cm$^{2}$ for 50 GeV$/c^{2}$ WIMPs.Comment: 6 pages, 2 Figures, Proceedings of International Symposium on Radiation Detectors and Their Uses (ISRD2016). Talk given on 19th Jan. 2016 by K.Fushimi. To be published in Proceedings will be published as JPS conference proceedings (2016

High-speed atomic force microscopy combined with inverted optical microscopy for studying cellular events.

A hybrid atomic force microscopy (AFM)-optical fluorescence microscopy is a powerful tool for investigating cellular morphologies and events. However, the slow data acquisition rates of the conventional AFM unit of the hybrid system limit the visualization of structural changes during cellular events. Therefore, high-speed AFM units equipped with an optical/fluorescence detection device have been a long-standing wish. Here we describe the implementation of high-speed AFM coupled with an optical fluorescence microscope. This was accomplished by developing a tip-scanning system, instead of a sample-scanning system, which operates on an inverted optical microscope. This novel device enabled the acquisition of high-speed AFM images of morphological changes in individual cells. Using this instrument, we conducted structural studies of living HeLa and 3T3 fibroblast cell surfaces. The improved time resolution allowed us to image dynamic cellular events

Experimental gold nephropathy in guinea pigs: Detection of autoantibodies to renal tubular antigens

Experimental gold nephropathy in guinea pigs: Detection of autoantibodies to renal tubular antigens. Renal tubular dysfunction was induced in Hartley guinea pigs by injection of sodium aurothiomalate (gold) as manifested by excretion of tubular basement membrane (TBM) antigen and renal tubular epithelial (RTE) antigen in urine and tubular proteinuria. Following the tubular dysfunction, autoimmune tubulointerstitial nephritis (TIN) and/or immune complex nephropathy (ICN) developed in a large proportion of animals. TIN was associated with anti-TBM antibodies, and the histological features were characterized by tubular lesions with interstitial mononuclear cell infiltration, destruction of tubules, and interstitial fibrosis. In ICN, the glomerular lesions consisted of partial thickening of capillary walls and mesangial cellularity, and granular immune deposits were seen in the mesangial area and on capillary walls. Furthermore, electron-dense deposits were demonstrated in the mesangial area and in the glomerular basement membrane (GBM) by electron microscopy. Anti-RTE antibodies were detected in the sera and eluates from the kidney of animals with ICN. RTE antigens were also detected in the glomerular deposits by indirect immunofluorescence using anti-guinea pig RTE antibody. These results suggest that TBM and RTE antigens released from renal tubules damaged by a direct toxic action of gold may lead to antibody formation against these antigens and induce TIN and/or ICN

Concomitant Nrf2- and ATF4-Activation by Carnosic Acid Cooperatively Induces Expression of Cytoprotective Genes

Carnosic acid (CA) is a phytochemical found in some dietary herbs, such as Rosmarinus officinalis L., and possesses antioxidative and anti-microbial properties. We previously demonstrated that CA functions as an activator of nuclear factor, erythroid 2 (NF-E2)-related factor 2 (Nrf2), an oxidative stress-responsive transcription factor in human and rodent cells. CA enhances the expression of nerve growth factor (NGF) and antioxidant genes, such as HO-1 in an Nrf2-dependent manner in U373MG human astrocytoma cells. However, CA also induces NGF gene expression in an Nrf2-independent manner, since 50 μM of CA administration showed striking NGF gene induction compared with the classical Nrf2 inducer tert-butylhydroquinone (tBHQ) in U373MG cells. By comparative transcriptome analysis, we found that CA activates activating transcription factor 4 (ATF4) in addition to Nrf2 at high doses. CA activated ATF4 in phospho-eIF2α- and heme-regulated inhibitor kinase (HRI)-dependent manners, indicating that CA activates ATF4 through the integrated stress response (ISR) pathway. Furthermore, CA activated Nrf2 and ATF4 cooperatively enhanced the expression of NGF and many antioxidant genes while acting independently to certain client genes. Taken together, these results represent a novel mechanism of CA-mediated gene regulation evoked by Nrf2 and ATF4 cooperation

A Substellar Companion to the Intermediate-Mass Giant 11 Com

We report the detection of a substellar companion orbiting the intermediate-mass giant star 11 Com (G8 III). Precise Doppler measurements of the star from Xinglong station and Okayama Astrophysical Observatory (OAO) revealed Keplerian velocity variations with an orbital period of 326.03 +/- 0.32 days, a semiamplitude of 302.8 +/- 2.6 m/s, and an eccentricity of 0.231 +/- 0.005. Adopting a stellar mass of 2.7 +/- 0.3 M_solar, the minimum mass of the companion is 19.4 +/- 1.5 M_Jup, well above the deuterium burning limit, and the semimajor axis is 1.29 +/- 0.05 AU. This is the first result from the joint planet search program between China and Japan aiming at revealing statistics of substellar companions around intermediate-mass giants. 11 Com b emerged from 300 targets of the planet search program at OAO. The current detection rate of a brown dwarf candidate seems to be comparable to that around solar-type stars within orbital separations of $\sim$3 AU.Comment: 19 pages, 4 figures, accepted by Ap