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Using Na-encapsulated benzo[18]crown-6 (Na)(B18C6) as a counter cation, we successfully magnetically isolated a fluoride-bridging Dy dinuclear complex {[(PW11O39)Dy(H2O)(2)](2)F} (Dy2POM) with lacunary Keggin ligands. (Na)(B18C6) formed two types of tetramers through C-HMIDLINE HORIZONTAL ELLIPSISO, pi MIDLINE HORIZONTAL ELLIPSIS pi and C-HMIDLINE HORIZONTAL ELLIPSIS pi interactions, and each tetramer aligned in one dimension along the c-axis to form two types of channels. One channel was partially penetrated by a supramolecular cation from the +/- a-axis direction, dividing the channel in the form of a bamboo node. Dy2POM was spatially divided by this bamboo node, which magnetically isolated one portion from the other. The temperature dependence of the magnetic susceptibility indicated a weak ferromagnetic interaction between the Dy ions bridged by fluoride. Dy2POM exhibited the magnetic relaxation characteristics of a single-molecule magnet, including the dependence of AC magnetic susceptibility on temperature and frequency. Magnetic relaxation can be described by the combination of thermally active Orbach and temperature-independent quantum tunneling processes. The application of a static magnetic field effectively suppressed the relaxation due to quantum tunneling.

Due to their rarity and diversity, sarcomas are difficult to diagnose. Consequently, there is an urgent demand for a novel diagnostic test for these cancers. In this study, we investigated serum miRNA profiles from 1002 patients with bone and soft tissue tumors representing more than 43 histological subtypes, including sarcomas, intermediate tumors, and benign tumors, to determine whether serum miRNA profiles could be used to specifically detect sarcomas. Circulating serum miRNA profiles in sarcoma patients were clearly distinct from those in patients with other types of tumors. Using the serum levels of seven miRNAs, we developed a molecular detector, Index VI, that could distinguish sarcoma patients from benign and healthy controls with remarkably high sensitivity (90%) and specificity (95%), regardless of histological subtype. Index VI provides an approach to the early and precise detection of sarcomas, potentially leading to curative treatment and longer survival., Sarcomas are rare malignant tumours of bone and soft tissue whose diagnosis remain difficult. Here, the authors analyse serum samples from over 1000 patients and using separate discovery, training and validation cohorts, identify and validate a 7-microRNA index that distinguishes malignant sarcomas from benign disease.

Up to 30% stage I lung cancer patients suffer recurrence within 5 years of curative surgery. We sought to improve existing protein-coding gene and microRNA expression prognostic classifiers by incorporating epigenetic biomarkers.Genome-wide screening of DNA methylation and pyrosequencing analysis of HOXA9 promoter methylation were performed in two independently collected cohorts of stage I lung adenocarcinoma. The prognostic value of HOXA9 promoter methylation alone and in combination with mRNA and miRNA biomarkers was assessed by Cox regression and Kaplan-Meier survival analysis in both cohorts.Promoters of genes marked by polycomb in embryonic stem cells were methylated de novo in tumors and identified patients with poor prognosis. The HOXA9 locus was methylated de novo in stage I tumors (p0.0005). High HOXA9 promoter methylation was associated with worse cancer-specific survival (hazard ratio [HR], 2.6; p = 0.02) and recurrence-free survival (HR, 3.0; p = 0.01), and identified high-risk patients in stratified analysis of stages IA and IB. Four protein-coding gene (XPO1, BRCA1, HIF1α, and DLC1), miR-21 expression, and HOXA9 promoter methylation were each independently associated with outcome (HR, 2.8; p = 0.002; HR, 2.3; p = 0.01; and HR, 2.4; p = 0.005, respectively), and when combined, identified high-risk, therapy naive, stage I patients (HR, 10.2; p = 3 × 10). All associations were confirmed in two independently collected cohorts.A prognostic classifier comprising three types of genomic and epigenomic data may help guide the postoperative management of stage I lung cancer patients at high risk of recurrence.

The present study aimed to identify genes associated with patient survival to improve our understanding of the underlying biology of gliomas. We investigated whether the expression of genes selected using random survival forests models could be used to define glioma subgroups more objectively than standard pathology. The RNA from 32 non‐treated grade 4 gliomas were analyzed using the GeneChip Human Genome U133 Plus 2.0 Expression array (which contains approximately 47 000 genes). Twenty‐five genes whose expressions were strongly and consistently related to patient survival were identified. The prognosis prediction score of these genes was most significant among several variables and survival analyses. The prognosis prediction score of three genes and age classifiers also revealed a strong prognostic value among grade 4 gliomas. These results were validated in an independent samples set (n = 488). Our method was effective for objectively classifying grade 4 gliomas and was a more accurate prognosis predictor than histological grading.

Liver metastasis is a major lethal complication associated with colon cancer, and post‐intravasation steps of the metastasis are important for its clinical intervention. In order to identify inhibitory microRNAs (miRNAs) for these steps, we performed ‘dropout’ screens of a miRNA library in a mouse model of liver metastasis. Functional analyses showed that miR‐493 and to a lesser extent miR‐493 * were capable of inhibiting liver metastasis. miR‐493 inhibited retention of metastasized cells in liver parenchyma and induced their cell death. IGF1R was identified as a direct target of miR‐493, and its inhibition partially phenocopied the anti‐metastatic effects. High levels of miR‐493 and miR‐493 * , but not pri‐miR‐493, in primary colon cancer were inversely related to the presence of liver metastasis, and attributed to an increase of miR‐493 expression during carcinogenesis. We propose that, in a subset of colon cancer, upregulation of miR‐493 during carcinogenesis prevents liver metastasis via the induction of cell death of metastasized cells.

MicroRNA (miRNA), non-coding RNA of approximately 22 nucleotides, post-transcriptionally represses expression of its target genes. miRNA regulates a variety of biological processes such as cell proliferation, cell death, development, stemness and genomic stability, not only in physiological conditions but also in various pathological conditions such as cancers. More than 1000 mature miRNA have been experimentally identified in humans and mice, yet the functions of a vast majority of miRNA remain to be elucidated. Identification of novel cancer-associated miRNA seems promising considering their possible application in the development of novel cancer therapies and biomarkers. Currently, there are two major approaches to identify miRNA that are associated with cancer: expression profiling study and functional screening assay. The former approach is widely used, and a large number of studies have shown aberrant miRNA expression profiles in cancer tissues compared with their non-cancer counterparts. Although aberrantly expressed miRNA are potentially good biomarkers, in most cases a majority of them do not play causal roles in cancers when functional assays are performed. In contrast, the latter approach allows screening of 'driver' miRNA with cancer-associated phenotypes, such as cell proliferation and cell invasion. Thus, this approach might be suitable in finding crucial targets of novel cancer therapy. The combination of both types of approaches will contribute to further elucidation of the cancer pathophysiology and to the development of a novel class of cancer therapies and biomarkers.

Background: Chemotherapy with or without radiotherapy is the mainstay of treatment for primary central nervous system lymphoma (PCNSL). High-dose methotrexate (MTX) is the most effective drug available to treat these lesions, either as a single agent or in combination with other drugs. Due to the lack of well-conducted randomized trials, the optimal treatment remains controversial. Available retrospective studies are difficult to discuss, however, some common themes can be found. Methods: One hundred and twelve patients with PCNSL were treated with four different regimens over a period of 24 years. Treatment regimens were: whole-brain irradiation (WBI) alone, MVP (MTX, vincristine, and predonisolone), ProMACE-MOPP hybrid (cyclophosphamide, pirarubicin, etoposide, vincristine, procarbazine, prednisone, and MTX) and R-MTX (rituximab, MTX, pirarubicin, procarbazine, and prednisone) combined-modality therapy. Results: The median failure-free survival was 16 months, and the median overall survival (OS) was 24 months. The 2- and 5-year actuarial probability of survival was 52.4+4.8% [95% confidence intervals (CI)] and 30.2+4.8% (95% CI), respectively. The ProMACEMOPP protocol, Karnofsky performance status (KPS), MTX dose and WBI were associated with good OS by univariate models. By multivariate analysis, MTX dose, WBI dose, and its square dose were significantly associated with good OS. 20‐30 Gy WB, and 500 mg/m 2 of MTX dose appeared important determinants of OS. Conclusions: A modest dose of MTX (500 mg/m 2 ) followed by reduced-dose WBI for patients who respond appears a feasible treatment approach that minimizes serious toxicity.

In mice, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) induces a high incidence of malignant lymphoma and leukemia, but exhibits little, if any, carcinogenic activity in the large intestine after long-term exposure. However, recent studies have revealed that colonic adenocarcinomas can be efficiently and rapidly induced by combined treatment with PhIP and dextran sulfate sodium (DSS), a potent inducer of colitis. In the present study, the authors investigated the effects of inflammation on PhIP-induced carcinogenesis using two mouse strains, C57BL/6J and MSM/Ms, showing distinct temporal profiles of inflammatory responses to DSS. A long-term carcinogenesis experiment conducted with a single i.g. administration of PhIP (200 mg/kg body weight), followed by DSS treatment in drinking water for 4-6 days, revealed an increase in tumor incidence in C57BL/6J mice in accordance with the DSS intake. In contrast, neoplastic lesions were rarely observed in the MSM/Ms strain. From the short-term exposure to DSS for 4 days, C57BL/6J mice demonstrated severe chronic colitis, accompanied by hyperplastic cryptal epithelium and extensive cellular infiltration. Splenomegaly and swelling of mesenteric lymph nodes were also evident for over 1 month as chronic symptoms of systemic immunological disturbance. However, no inflammatory lesions were detected in MSM/Ms mice. The present results provide strong evidence that prolonged chronic inflammatory responses induced by DSS are directly responsible for the observed enhancement of PhIP-induced large bowel carcinogenicity.

The biological function of hnRNP family proteins is widely diverse and involved in pre-mRNA processing, transcriptional regulation, recombination, and telomere maintenance. In the course of our study on the elucidation of biological functions of minisatellite DNA, we isolated several nuclear proteins that bind to the mouse minisatellite Pc-1, which consists of a tandem array of d(GGCAG) repeats, from NIH3T3 cells. One of the minisatellite binding proteins, MNBP-A, which binds to a single-stranded G-rich strand of the Pc-1 repeat, was proven identical to the hnRNP A3. Recombinant hnRNP A3 was demonstrated to bind to the single-stranded telomeric d(TTAGGG) repeat with much higher affinity than the d(GGCAG) repeat. Binding of hnRNP A3 to the single-stranded telomeric repeat protected the repeat from nuclease attack, and inhibited both telomerase reaction and DNA synthesis in vitro. These results suggest a possible biological role of hnRNP A3 in the stable maintenance of telomere repeats.

To cite this Article: Yamanaka, Ryuya, Homma, Junpei, Sano, Masakazu, Tsuchiya, Naoto, Yajima, Naoki, Shinbo, Yoshikatsu, Hasegawa, Akira, Onda, Kiyoshi and Tanaka, Ryuichi , 'Immuno-chemotherapy with a combination of rituximab, methotrexate, pirarubicin and procarbazine for patients with primary CNS lymphoma A preliminary report', Leukemia and Lymphoma, 48:5, 1019 1022 To link to this article: DOI: 10.1080/10428190701248009 URL: http://dx.doi.org/10.1080/10428190701248009

Okadaic acid-sensitve serine/threonine protein phosphatase 5 (PP5) is expressed ubiquitously in various tissues and is considered to participate in many cellular processes. PP5 has a catalytic domain in the C-terminal region and three tetratricopeptide repeat (TPR) motifs in the N-terminal region, which are suspected to function as a protein–protein interaction domain. Physiological roles of PP5 are still largely unknown, although several PP5-binding proteins were reported and a few in vivo functions of PP5 were suggested. In the present study, the effects of expression of the full-length wild-type PP5 fused with EGFP (EGFP-PP5WT) and its phosphatase-dead mutant EGFP-PP5H304A were investigated. Transient expression of either EGFP-PP5WT or EGFP-PP5H304A in HeLa cells induced deformed nuclei with a 10-fold frequency compared to that of EGFP. Abnormal-shaped nuclei were also substantially increased by induced moderate expression of PP5 in tet-on HeLa cells. Many HeLa cells expressing EGFP-PP5WT possessed multi-nuclei separated from each other by nuclear membrane, while expression of EGFP-PP5H304A induced deformed nuclei which were multiple-like in shape, but not separated completely and were surrounded by one nuclear membrane. These results suggest that PP5 plays important roles at the M-phase of the cell cycle, especially in separation of chromosomes and formation of nuclear membrane. J. Cell. Biochem. 101: 321–330, 2007. © 2006 Wiley-Liss, Inc.

We report the efficacy of salvage therapy with a modified ProMACE-MOPP combined with radiation in patients with primary central nervous system lymphoma (PCNSL). Thirty-two immunocompetent patients were treated with a regimen of pirarubicin, cyclophosphamide, etoposide, vincristin, and methotrexate (MTX: 500 mg/m(2)) administered in 21-day cycles. Patients received 20 Gy of whole-brain radiotherapy after three cycles of chemotherapy. A single cycle of chemotherapy was repeated every four months for two years. Nine patients with CNS relapse were retreated with additional cycles of the ProMACE-MOPP hybrid regimen with a 90% objective response rate. Median complete response (CR) duration was 13.2 months and median survival time (MST) for the nine patients treated after initial relapse was 30 months. One of 17 patients (5.8%) who had less than 20 Gy of whole brain irradiation developed dementia. In contrast, six of seven (85.7%) patients who had more than 30 Gy of whole brain radiotherapy became demented. Maintaining a moderate dose of MTX, while adding chemotherapeutic agents and 20 Gy of whole brain radiation therapy, improved disease control and overall survival and lowered the incidence of delayed neurologic toxicity in patients with PCNSL. Additional treatment with a ProMACE-MOPP hybrid regimen is still effective for relapsed disease.

Mammalian genomes contain several types of repetitive sequences. Some of these sequences are implicated in various specific cellular events, including meiotic recombination, chromosomal breaks and transcriptional regulation, and also in several human disorders. In this review, we document the formation of DNA secondary structures by the G-rich repetitive sequences that have been found in several minisatellites, telomeres and in various triplet repeats, and report their effects on in vitro DNA synthesis. d(GGCAG) repeats in the mouse minisatellite Pc-1 were demonstrated to form an intra-molecular folded-back quadruplex structure (also called a G4' structure) by NMR and CD spectrum analyses. d(TTAGGG) telomere repeats and d(CGG) triplet repeats were also shown to form G4' and other unspecified higher order structures, respectively. In vitro DNA synthesis was substantially arrested within the repeats, and this could be responsible for the preferential mutability of the G-rich repetitive sequences. Electrophoretic mobility shift assays using NIH3T3 cell extracts revealed heterogeneous nuclear ribonucleoprotein (hnRNP) A1 and A3, which were tightly and specifically bound to d(GGCAG) and d(TTAGGG) repeats with K(d) values in the order of nM. HnRNP A1 unfolded the G4' structure formed in the d(GGCAG)(n) and d(TTAGGG)(n) repeat regions, and also resolved the higher order structure formed by d(CGG) triplet repeats. Furthermore, DNA synthesis arrest at the secondary structures of d(GGCAG) repeats, telomeres and d(CGG) triplet repeats was efficiently repressed by the addition of hnRNP A1. High expression of hnRNPs may contribute to the maintenance of G-rich repetitive sequences, including telomere repeats, and may also participate in ensuring the stability of the genome in cells with enhanced proliferation. Transcriptional regulation of genes, such as c-myc and insulin, by G4 sequences found in the promoter regions could be an intriguing field of research and help further elucidate the biological functions of the hnRNP family of proteins in human diseases.

Better understanding of the underlying biology of malignant gliomas is critical for the development of early detection strategies and new therapeutics. This study aimed to define genes associated with survival. We investigated whether genes coupled with a class prediction model could be used to define subgroups of high-grade gliomas in a more objective manner than standard pathology. RNAs from 29 malignant gliomas were analysed using Agilent microarrays. We identified 21 genes whose expression was most strongly and consistently related to patient survival based on univariate proportional hazards models. In six out of 10 genes, changes in gene expression were validated by quantitative real-time PCR. After adjusting for clinical covariates based on a multivariate analysis, we finally obtained a statistical significance level for DDR1 (discoidin domain receptor family, member 1), DYRK3 (dual-specificity tyrosine-(Y)-phosphorylation-regulated kinase 3) and KSP37 (Ksp37 protein). In independent samples, it was confirmed that DDR1 protein expression was also correlated to the prognosis of glioma patients detected by immunohistochemical staining. Furthermore, we analysed the efficacy of the short interfering RNA (siRNA)-mediated inhibition of DDR1 mRNA synthesis in glioma cell lines. Cell proliferation and invasion were significantly suppressed by siRNA against DDR1. Thus, DDR1 can be a novel molecular target of therapy as well as an important predictive marker for survival in patients with glioma. Our method was effective at classifying high-grade gliomas objectively, and provided a more accurate predictor of prognosis than histological grading.

Fragile X syndrome is caused by expansion of a d(CGG) triplet repeat in the 5'-untranslated region of the first exon of the FMR1 gene resulting in silencing of the gene. The d(CGG) repeat has been reported to form hairpin and quadruplex structures in vitro, and formation of these higher structures could be responsible for its unstable expansion in the syndrome, although molecular mechanisms underlying the repeat expansion still remain elusive. We have previously proved that UP1, a proteolytic product of hnRNP A1, unfolds the intramolecular quadruplex structures of d(GGCAG)5 and d(TTAGGG)4 and abrogates the arrest of DNA synthesis at d(GGG)n sites. Here, we demonstrate that the d(CGG) repeat forms a peculiar DNA structure, which deviates from the canonical B-form structure. In addition, UP1 was demonstrated by CD spectrum analysis to unfold this characteristic higher structure of the d(CGG) repeat and to abrogate the arrest of DNA synthesis at the site. This ability of UP1 suggests that unfolding of unusual DNA structures of a triplet repeat is required for DNA synthesis processes.

LRP130 (also known as a LRPPRC) is an RNA and single-stranded DNA-binding protein, and recently identified as a candidate gene responsible for the Leigh syndrome, a French-Canadian type cytochrome c oxidase deficiency. However, the biological function of LRP130 still remains largely unresolved. In the present study, we found that the C-terminal half of the mouse LRP130 located within a 120 amino acid sequence (a.a. 845–964) binds to synthetic RNA homopolymers, poly(G), poly(U), and poly(C), as well as r(CUGCC)6. Assessment of the subcellular localization indicated both nuclear/endoplasmic reticulum (ER) and mitochondrial fractions to be positive. To further analyze the subcellular localization of LRP130, a nuclear/ER fraction was fractionated into the nucleoplasm (NP) and nuclear envelope (NE)/ER, and the latter was further separated into outer nuclear membrane (ONM)/ER and inner nuclear membrane (INM) by treatment with Triton X-100. LRP130 was detectable in all three fractions, and the distribution pattern was in good accordance with that known for ONM/ER proteins. Interestingly, immunostaining of HeLa cells demonstrated nuclear rim staining of LRP130, specifically at the outside of the NE and also at ER, and association of LRP130 with poly(A)+ RNA was restricted only to the ONM/ER fraction. Overexpression of full-length mouse LRP130 fused with EGFP resulted in nuclear accumulation of poly(A)+ RNA in HeLa cells. Taking all these results together, it is suggested that LRP130, a novel type of RNA-binding protein, associates with mRNA/mRNP complexes at the outside of NE and ER, and plays a role in control of mRNA metabolisms.

Recently, we have identified and purified minisatellite DNA binding proteins (MNBPs) that bind to the mouse hypervariable minisatellite Pc-1, from NIH3T3 cells. This study describes the isolation and characterization of a mouse leucine-rich protein (mLRP130) as one of the MNBPs that binds to the C-rich strand of Pc-1. The mLRP130 cDNA was demonstrated to encode a polypeptide of 1306 amino-acid residues with a deduced molecular mass of 137 kDa, and the mLRP130 mRNA is detected in various organs, including heart, brain, liver, skeletal muscle, kidneys and testes. The mLRP130 protein has nine copies of pentatricopeptide repeat (PPR) motifs that are considered to serve as protein–protein interactions. Two forms of the mLRP130 protein were detected in NIH3T3 cells with an approximate molecular mass of 140 kDa (mLRP130) and 100 kDa (mLRP130der), and were detected mainly in nuclear and cytoplasmic fractions, respectively. Immunofluorescence microscopic analysis demonstrated dominant localization of mLRP130 at the perinuclear region, and also in the nucleus and cytoplasm with dot- or squiggle-like staining. The immunoprecipitated mLRP130 bound to the single-stranded d(CTGCC)8, but not to its complementary G-rich strand of d(GGCAG)8 or double-stranded form. Possible biological roles of mLRP130 are discussed in association with the stability of minisatellite DNA sequences.

Fragile X syndrome is caused by expansion of a d(CGG) triplet repeat in the 5'-untranslated region of the first exon of the FMR1 gene resulting in silencing of the gene. The d(CGG) repeat has been reported to form hairpin and quadruplex structures in vitro, and formation of these higher structures could be responsible for its unstable expansion in the syndrome, although molecular mechanisms underlying the repeat expansion still remain elusive. We have previously proved that UP1, a proteolytic product of hnRNP A1, unfolds the intramolecular quadruplex structures of d(GGCAG)5 and d(TTAGGG)4 and abrogates the arrest of DNA synthesis at d(GGG)n sites. Here, we demonstrate that the d(CGG) repeat forms a peculiar DNA structure, which deviates from the canonical B-form structure. In addition, UP1 was demonstrated by CD spectrum analysis to unfold this characteristic higher structure of the d(CGG) repeat and to abrogate the arrest of DNA synthesis at the site. This ability of UP1 suggests that unfolding of unusual DNA structures of a triplet repeat is required for DNA synthesis processes.

In this study, we demonstrate that tumor lysate-loaded dendritic cells can elicit a specific CD8+ cytotoxic T lymphocyte response against autologous tumor cells in patients with malignant glioma. CTL from three of five patients expressed strong cytolytic activity against autologous glioma cells, did not lyse autologous lymphoblasts and were variably cytotoxic against the LAK-sensitive cell line Daudi. Also, DCs pulsed normal brain lysate failed to induce cytolytic activity against autologous glioma cells, suggesting the lack of autoimmune response. Two of five patients CD8+ T cells expressed a modest cytotoxicity against autologous glioma cells. CD8+ T cells isolated during these ineffective primings secreted large amounts of IL-10, less amounts of IFN-gamma as detected by ELISA, Type 2 bias in the CD8+ T cell response accounts for the lack of cytotoxic effector function from these patients. Cytotoxicity against autologous glioma cells could be significantly inhibited by anti-HLA class I antibody. These data demonstrate that tumor lysate-loaded DC can be an effective tool in inducing glioma-specific CD8+ CTL able to kill autologous glioma cells in vitro. However, high levels of tumor specific tolerance in some patients may account for a significant barrier to therapeutic vaccination. Moreover, cytotoxic responses were augmented by transfecting DC with the gene for IL-18. For all five patients, CD8+T cells treated with IL18 transfected DC produced Th1 response. These results may have important implications for the treatment of malignant glioma patients with immunotherapy. DCs loaded with total tumor lysate and IL-18 may represent a method for inducing Th1 immunoresponses against the entire repertoire of glioma antigens.

Recently, we have identified and purified minisatellite DNA binding proteins (MNBPs) that bind to the mouse hypervariable minisatellite Pc-1, from NIH3T3 cells. This study describes the isolation and characterization of a mouse leucine-rich protein (mLRP130) as one of the MNBPs that binds to the C-rich strand of Pc-1. The mLRP130 cDNA was demonstrated to encode a polypeptide of 1306 amino-acid residues with a deduced molecular mass of 137 kDa, and the mLRP130 mRNA is detected in various organs, including heart, brain, liver, skeletal muscle, kidneys and testes. The mLRP130 protein has nine copies of pentatricopeptide repeat (PPR) motifs that are considered to serve as protein-protein interactions. Two forms of the mLRP130 protein were detected in NIH3T3 cells with an approximate molecular mass of 140 kDa (mLRP130) and 100 kDa (mLRP130der), and were detected mainly in nuclear and cytoplasmic fractions, respectively. Immunofluorescence microscopic analysis demonstrated dominant localization of mLRP130 at the perinuclear region, and also in the nucleus and cytoplasm with dot- or squiggle-like staining. The immunoprecipitated mLRP130 bound to the single-stranded d(CTGCC)8, but not to its complementary G-rich strand of d(GGCAG)8 or double-stranded form. Possible biological roles of mLRP130 are discussed in association with the stability of minisatellite DNA sequences.

We isolated a cDNA encoding a novel heterogeneous nuclear ribonucleoprotein (hnRNP)-like protein on DNA affinity screening of a K562 cDNA expression library with an oligodeoxynucleotide (JKT41) derived from intron 9 of the human myeloperoxidase gene. The cDNA has a 1,305 bp sequence that encodes a polypeptide of 301 amino acid residues. The protein, named JKTBP, contains two repeats of a putative RNA binding domain (RBD), each composed of canonical RNP-2 and RNP-1 motifs, and a glycine- and tyrosine-rich carboxyl terminus. The sequences of these two repeats are highly homologous with those of the 2 x RBD-Gly rich group of hnRNPs. Northern blotting showed that two mRNAs of approximately 1.4 and 2.8 kb were present in most cultured cells examined. The recombinant protein expressed in Escherichia coli interacted with the double-stranded form of JKT41 as well as with its single-stranded form. This interaction was competitively inhibited by the same unlabeled JKT41 and to nearly the same extent by unrelated oligonucleotides. Moreover, the recombinant protein interacted with poly(G) and poly(A), but not with poly(U) or poly(C). Transient expression of the protein in SKM-1 cells repressed the expression of chloramphenicol acetyltransferase reporter genes located downstream of the intron 9 element of JKT41 or intron 7 element of FERE27. The implications of the protein in the biogenesis of mRNA are discussed.

The mechanism for the decrease in the accumulation of cadmium (Cd) in Cd-resistant Chinese hamster V79 (Cdr) cells in culture was investigated in a comparison with Cd-sensitive (Cds) cells. Both Cdr and Cds cells took up Cd in a time-dependent manner but the rate of uptake of Cd by Cdr cells was about 15% of that by Cds cells. Kinetic studies of the uptake of Cd showed that the Vmax values for Cdr and Cds cells were 0.31 and 0.46 pmol Cd/h per mg protein, respectively. The Km values were 31.95 microM for Cdr cells and 3.15 microM for Cds cells. Mersalyl acid, a sulfhydryl (SH) blocker to which cells are impermeable, inhibited the uptake of Cd by Cds cells at subtoxic concentrations while Cdr cells were insensitive to inhibition by mersalyl acid, suggesting that SH groups in the plasma membrane play a role in the uptake of Cd. Uptake of Cd by Cds cells was dependent on the pH of the incubation medium and the rate of uptake was very high at pH 7.4 and pH 8.0 relative to the rates at pH 6.0 and pH 6.8. By contrast, the uptake of Cd by Cdr cells was lower at all pH values than that by Cds cells. The decrease in the rate of uptake of Cd by Cdr cells could not be ascribed to an increase in the efflux of Cd. A Cd-blotting technique was used to detect plasma membrane proteins with high affinity for Cd. Two major differences in terms of Cd-binding proteins (Cd-BPs) were observed between Cdr and Cds cells. A 110-kDa Cd-BP, detected in Cds cells, was found at a reduced level in Cdr cells, while an 82-kDa Cd-BP, which was not observed in Cds cells, was detected in Cdr cells.