Identification of new subunits of the multiprotein mammalian TRRAP/TIP60-containing histone acetyltransferase complex

The mammalian ATM/PI 3-kinase-related TRRAP protein was previously found to be a component of a multi-protein histone acetyltransferase (HAT) complex containing the HAT TIP60. In this report, we identify a previously uncharacterized protein encoded by the FLJ10914 ORF, which we designate MRGBP, as a new component of the TRRAP/TIP60 HAT complex. In addition, through purification of MRGBP and its associated proteins from HeLa cell nuclear extracts, we identify the thyroid receptor coactivating protein (TRCp120), DMAP1, and the related MRG15 and MRGX proteins as MRGBP-associating proteins, and we present biochemical evidence that they are previously unrecognized components of the TRRAP/TIP60 HAT complex. Taken together, our findings shed new light on the structure and function of the mammalian TRRAP/TIP60 histone acetyltransferase complex.     

Levels and behavior of 2-phenylbenzotoriazole-type mutagens in the effluent of a sewage treatment plant

We previously reported on the isolation and structural determination of five 2-phenylbenzotriazole (PBTA)-type mutagens (PBTA-1, PBTA-2, PBTA-3, PBTA-4 and PBTA-6) in blue rayon/cotton adsorbed substances collected from surface waters at sites located downstream of sewage treatment plants. We also noted that PBTA-1 and PBTA-2 were discharged from sewage treatment plants and subsequently diluted or decomposed while moving down the Yodo River system. However, it has not been investigated whether they are commonly discharged from sewage treatment plants into rivers. The main purpose of this study was to make a comprehensive survey of levels and behavior of PBTA-type mutagens in effluents discharged from the sewage treatment plant located along the bank of the Uji River, one tributary of the Yodo River system. Water samples were collected at the outlet of the sewage treatment plant for 16 consecutive days in May 1999 and 11 consecutive days in December 1999. Organic constituents were obtained via sorption to blue rayon and subsequent methanol elution. Extract mutagenic activity was measured using Salmonella typhimurium YG1024 with metabolic activation. PBTA-type mutagens (PBTA-1, PBTA-2, PBTA-3, PBTA-4, PBTA-5 and PBTA-6) were quantified by HPLC with electrochemical detection, followed by HPLC purification on reverse-phase columns. The study showed that PBTA-2, PBTA-3, PBTA-4 and PBTA-6 were detected in most samples. The total contribution of these four PBTA-type mutagens to overall extract mutagenicity is on average 33% for the May 1999 sample and 58% for the December 1999 sample. The individual PBTA compounds that had the largest contribution to the overall mutagenicity were PBTA-3 and PBTA-4, accounting for 11 and 16% in May 1999, and 25 and 26% in December 1999. A further comparative study was done in December 1999 using the blue rayon hanging method and the results were similar to those obtained using the blue rayon column method. In conclusion, the present study showed that PBTA-2, PBTA-3, PBTA-4 and PBTA-6 were commonly discharged from a sewage treatment plant into the Uji River, and they accounted for a substantial portion of the effluent mutagenicity.     

Pyruvate:NADP+ oxidoreductase is stabilized by its cofactor,thiamin pyrophosphate,in mitochondria of Euglena gracilis

Pyruvate:NADP(+) oxidoreductase (PNO) is a thiamin pyrophosphate (TPP)-dependent enzyme that plays a central role in the respiratory metabolism of Euglena gracilis, which requires thiamin for growth. When thiamin was depleted in Euglena cells, PNO protein level was greatly reduced, but its mRNA level was barely changed. In addition, a large part of PNO occurred as an apoenzyme lacking TPP in the deficient cells. The PNO protein level increased rapidly, without changes in the mRNA level, after supplementation of thiamin into its deficient cells. In the deficient cells, in contrast to the sufficient ones, a steep decrease in the PNO protein level was induced when the cells were incubated with cycloheximide. Immunofluorescence microscopy indicated that most of the PNO localized in the mitochondria in either the sufficient or the deficient cells. These findings suggest that PNO is readily degraded when TPP is not provided in mitochondria, and consequently the PNO protein level is greatly reduced by thiamin deficiency in E. gracilis.     

Pancreatoblastoma. A case report with special emphasis on squamoid corpuscles with optically clear nuclei rich in biotin

BACKGROUND: Pancreatoblastoma (PBL) is a rare neoplasm that generally occurs in the pediatric age group and shows unique histopathology, including squamoid corpuscles that may contain tumor cells with optically clear nuclei (OCN) rich in biotin. In the English-language literature there have been two reports on the cytology of PBL, but neither of them refers to the cytologic features of squamoid corpuscles. CASE: A 3-year-old boy with nausea and general fatigue was referred to our center. Imaging studies showed an approximately 7.5-cm, left-sided abdominal mass and multiple metastases in the lung. The abdominal mass was biopsied, and its histology showed solid cellular nests with occasional acinar differentiation and squamoid corpuscles. Imprint cytology of the biopsied sample displayed cellular epithelial nests with focal acinar structures and foci composed of larger cells with a low nuclear/cytoplasmic ratio. These foci contained a few tumor cells with biotin-rich OCN and were determined to be squamoid corpuscles. CONCLUSION: Detection of occasional squamoid corpuscles with biotin-rich OCN can be useful in making a diagnosis of PBL on cytologic samples.     

Effects of ionic valency of interacting metal elements in ion uptake by carrot (Daucas carota cv. U.S. harumakigosun)

Interaction of elements in the course of element uptake by carrot (Daucas carota cv. U.S. harumakigosun) exerted by the addition of elements, such as Rb, Zn, and Al, was investigated. For the purpose of precise evaluation of uptake behavior, the simultaneous determination of absorption of Na, Be, Sr, Mn, Co, Zn, Ce, Pm, and Gd was conducted by the multitracer technique. For root uptakes, Al exhibited its influence on the uptake of essential elements and on the uptake of toxic or unbeneficial ones, presumably as a result of the large electric valency that caused cell membrane disintegrity. On the other hand, Zn as a divalent cation only affected the uptake of essential and beneficial elements. Rubidium, which is a monovalent cation, did not exhibit any effect on the uptake of other ions. Concerning shoot uptakes, inhibition by Zn and Al, but not by Rb, was observed for the uptake of Sr, Mn, Co, and Zn. From the present investigation, it is suggested that there exists an interaction between added ions and the elements taken into plants and that the degree of interaction increases in the increasing order of ionic valency: M+ (Rb), M2+ (Zn), and M3+ (Al).     

Liposome immunoblotting assay using a substrate-forming precipitate inside immunoliposomes

A new immunoblotting assay which uses antibody-coupled liposomes containing horseradish peroxidase is proposed. A substrate 4-chloro-1-naphthol permeated through the phospholipid membrane of the antibody-coupled liposomes and formed a colored product precipitating inside the liposomes. The precipitates accumulated in the liposomes and could be detected at the positions where the liposomes coupled with a target in blotted samples. Combination of liposomes with average diameter of 350 nm and a PVDF membrane with a pore size of 450 nm, 0.02 ng of IgM was detected, while the conventional immunoblotting using antibody-HRP conjugates detected 2 ng of IgM. The sensitivity increased about two orders of magnitude by the liposome immunoblotting assay. This liposome immunoblotting assay gives a simple detection method of proteins with a high sensitivity, as well as a high sensitivity Western blotting assay.