Substituent effect of a fluorine atom on the mutagenicity of nitroquinolines

Some 16 nitroquinolines (NQs) and their fluorinated derivatives were tested for mutagenicity in Salmonella typhimurium TA100 without S9 mix to investigate the effect of fluorine-substitution on the mutagenicity. These NQs consist of 5-NQs, 5-nitroquinoline N-oxides (5-NQOs), N-methyl-5-nitroquinolinium methanesulfonates (N-Me-5-NQs) and 8-NQs, including three ortho-F-NQs, one meta-F-NQ, four para-F-NQs and four 3-F-NQs. For this purpose, eight F-NQs were newly synthesized. The data indicated that the ratio of the mutagenic activities (revertants/plate/nmol) of fluorinated NQs to those of the corresponding parent non-fluorinated compounds ranged from 0.6- to 119-fold. The fluorine atom located para to the nitro group markedly enhanced the mutagenicity (24-fold and more), while three ortho-fluorinated derivatives showed no significant increase in mutagenicity (enhancement ratio were 0.6, 0.8 and 1.7). With respect to 8-NQs, its meta-fluorinated derivative also had an enhanced mutagenicity over the parent compound (53-fold). In addition, although N-Me-5-NQ was less mutagenic than 5-NQ and 5-NQO, the mutagenicity of N-Me-5-NQ was most significantly enhanced by fluorine-substitution. These results suggest that introduction of a fluorine atom to the molecule in question may be a useful tool to modify their mutagenic potency and to better understand the mechanism of mutation.

Existence of acyl-CoA hydrolase-mediated pathway supplying arachidonic acid for prostaglandin synthesis in microsomes from rabbit kidney medulla

We have previously shown that acyl-coenzyme A (CoA) hydrolase that hydrolyzes arachidonoyl-CoA (AA-CoA) to arachidonic acid (AA) and CoA is present in the cytosol of rabbit kidney medulla and that this enzyme can supply AA for prostaglandin (PG) synthesis in this region. In the present study, the existence of the acyl-CoA hydrolase-mediated pathway that supplies AA available for PG synthesis in microsomes from the kidney medulla was examined. AA-CoA (20 microM) was preincubated with the 105,000 g pellet (microsomes, 0.5 mg of protein) from the medulla for 5 min at 37 degrees C followed by incubation with the medulla microsomes (0.5 mg of protein) (the source of PG synthesizing enzymes) in the presence of hydroquinone and reduced glutathione for 5 min at 37 degrees C. The PGs formed were measured by high-pressure liquid chromatography using 9-anthryldiazomethane for derivatization. The addition of the microsomal fraction from the medulla in the preincubation mixture increased total PG formation from 3.86 to 8.70 nmol, and this stimulatory effect was somewhat weaker than that of the cytosolic fraction. On the other hand, the microsomal fraction in the kidney cortex has an extremely lower capacity to supply AA for PG synthesis than do medulla microsomes. These results suggest that, in kidney medulla, the microsomes as well as the cytosol have the potential route that supplies AA from AA-CoA for PG synthesis and that this pathway is mediated by acyl-CoA hydrolase.

Multiple alternative transcripts of the human homologue of the mouse TRAD/R51H3/RAD51D gene, a member of the rec A/RAD51 gene family

Yeast RAD51, a homologue of Escherichia coli recA, plays a crucial role in mitotic and/or meiotic recombination and in the repair of double-strand DNA breaks. We have identified unique multiple alternative transcripts of a human TRAD/R51H3/RAD51D gene, a member of the recA/RAD51 gene family. One of the transcripts encoded a 328-amino-acid protein with 83.0% overall amino acid identity and 98. 2% similarity with the mouse TRAD gene and had two nucleotide binding consensus sequences, motif A and motif B, conserved among members of this family. Other transcripts encoded truncated proteins with a partial N-terminal region of the orthologue or short proteins lacking internal sequences which contain nucleotide binding motifs. Northern blot analysis revealed that multiple transcripts of the human TRAD gene were expressed in various tissues and their distribution was not ubiquitous.

Inhibitory effects of tetragalloylglucose and digalloylhamamelose on adhesion and in vitro invasion of mouse lung carcinoma cells

Tetragalloylglucose (TgG) and digalloylhamamelose (DgH) were found to inhibit adhesion to and invasion through Matrigel of mouse Lewis lung carcinoma LL2-Lu3 cells, which are highly metastatic. TgG inhibited matrix metalloproteinases (MMPs) from the tumor cells like (-)-epigallocatechin gallate, whereas DgH did not. These results suggest that TgG and DgH inhibit tumor cell invasion by inhibiting MMPs and/or cell adhesion of the tumor cells.

Initial daily interferon administration can gain more eradication of HCV-RNA in patients with chronic hepatitis C, especially with serum intermediate viral load

BACKGROUND/AIMS

We studied the effect of initial daily administration of interferon for the treatment of chronic hepatitis C, especially in patients with intermediate viral load.

METHODOLOGY

Consecutive patients who met the inclusion criteria were randomly enrolled into two groups in this study. All patients analyzed could be treated with interferon-alpha for 6 months. Patients in group A were administered 6 million units of interferon-alpha subcutaneously daily initially for 2 weeks and then thrice weekly. Patients in group B were treated with the same dose of interferon-alpha thrice weekly from the first administration. We decided the criteria of complete remission as the absence of serum HCV-RNA at both points of the end of interferon treatment and 6 months later.

RESULTS

Due to the relationship between the efficacy and serum viral load, we decided the criteria of the intermediate load as the quantitative value of serum HCV-RNA to be not lower than 10(5.0) and not higher than 10(6.5) copies/ml. Seventy-six and 78 patients, whose genotype and quantitative value of serum HCV-RNA could be measured before treatment, were analyzed in group A and B, respectively. The rate of complete remission in group A (40.8%) was higher than that in group B (25.6%), significantly (p = 0.046). In the intermediate viral load group, the rate of complete remission in group A (52.3%) was significantly higher than that in group B (29.3%) (p = 0.045). In the patients with genotype 1 b virus, the rate of complete remission had a tendency to be higher in group A (33.3%) than in group B (17.4%) (not significant). In the patients with genotype 2, the rate of complete remission was higher in group A (77.8%) than in group B (41.2%) (significant, p = 0.041).

CONCLUSIONS

These results suggest that the initial daily interferon administration is necessary to gain a higher rate of serum HCV-RNA eradication in patients with intermediate viral load in chronic hepatitis C.

Apoptosis-inducing activity of polyphenol compounds derived from tea catechins in human histiolytic lymphoma U937 cells

Polyphenolic compounds derived from tea catechins were examined for apoptosis-inducing activity in human histiolytic lymphoma U937 cells. (-)-Epigallocatechin gallate, theasinensin D, compound OH-5, theaflavin, and theaflavin digallate induced apoptosis as evidenced by DNA ladder formation, its inhibition by a caspase inhibitor, and chromatin condensation. Theasinensin D was the most potent inducer and the data suggest the importance of the number and three dimensional localization of their phenolic groups in this activity. These apoptosis-inducible compounds may be useful as a cancer chemopreventive and chemotherapeutic agent.

Effects of oligofluorine substitution on the mutagenicity of quinoline: a study with twelve fluoroquinoline derivatives

A total of 12 variously fluorinated derivatives of quinoline (Q) were tested for their mutagenicity in Salmonella typhimurium TA100 in the presence of S9 mix to investigate the structure-mutagenicity relationship in oligofluorinated quinolines. Nine of them, 3,7-di-, 5,6-di-, 6,7-di-, 6,8-di-, 7,8-di-, 3,5,7-tri-, 5,6,8-tri-, 6,7, 8-tri-, and 5,6,7,8-tetrafluoroquinolines (FQs), were newly synthesized for this purpose. Those fluorinated at position 3 were all non-mutagenic. Mutagenicity was enhanced by fluorine-substitution at position 5 or 7, but not in 3-FQs (i.e., 3, 5-di-, 3,7-di-, and 3,5,7-triFQs). Some of the 6-fluorinated derivatives showed less maximum induced-revertants with more mutagenic potencies in terms of induced-revertants per dose than quinoline. No marked change occurred by fluorine-substitution at position 8. These results show that the effect of di- and trifluoro-substitution on mutagenicity is generally additive, while that of tetrafluorination approaches the deactivating effect of perfluorination. Our study suggests that 3-fluorine-substitution in the pyridine moiety may be a useful means of antimutagenic structural modification in pyridine-fused aromatic chemicals for medicinal and agricultural use.

Cell-cycle-regulated phosphorylation of cAMP response element-binding protein: identification of novel phosphorylation sites

We report that the cAMP response element binding protein (CREB) undergoes cell-cycle-regulated phosphorylation. In human amnion FL cells, CREB was expressed as two forms with different molecular masses, 45 and 45.5 kDa. Although asynchronous cells contained predominantly the 45 kDa forms, this form shifted to 45.5 kDa when the cells were synchronized with the early S-phase. Furthermore the expression of the 45.5 kDa band was increased when cells were treated with okadaic acid, confirming that the 45.5 kDa band was a phosphorylated form of the 45 kDa band. Mutation analysis indicated that neither Ser133, the target of cAMP-dependent protein kinase and calcium calmodulin kinase, nor Ser129, the target of glycogen synthetase kinase 3, was responsible for the expression of the 45.5 kDa band, but that Ser108, Ser111 and Ser114, located in a region matching the consensus sequence for the casein kinase II target, were required. A mutant in which Ser111 and Ser114 were each replaced by a glutamic residue, mimicking a phosphorylated state, had a higher activation potential in cAMP response element-mediated transcription. These results strongly suggest that the casein kinase II target region is involved in cell cycle-regulated phosphorylation of the CREB protein and also in transcriptional enhancement.

The long-term evaluation of pulmonary toxicity following isolated lung perfusion with melphalan in the rat

The present study was conducted to evaluate the long-term pulmonary toxicity of isolated lung perfusion (ILP) with melphalan in the rat model. F344 rats were treated by ILP with 1 mg of melphalan or buffered hespan (BHE). The rats in the melphalan group were sacrificed randomly 30, 60, 90, 120, 150, and 180 days after the perfusion. Pulmonary toxicity was evaluated by pathological analysis. In the melphalan group, light and electron microscopic findings revealed perivascular and peribronchial edema, and septal thickening with cellular infiltration of the interstitial space 30 days after the perfusion, but all of these changes had disappeared by 60 days. Azan stain showed a slight increase of the connective tissue at the alveolar wall in the melphalan group, but no progressive pulmonary interstitial fibrosis was observed after 180 days. Transmission electron microscopy showed minimal proliferation of the type II pneumocytes of normal appearance in the melphalan group. In conclusion, the long-term pulmonary toxicity of ILP with melphalan is acceptable; however clinical trials of this therapy need to be conducted.

Vanadium accumulation in pinnipeds

Vanadium in four species of pinnipeds (northern fur seals [Callorhinus ursinus], Steller sea lions [Eumetopias jubatus], harbor seals [Phoca vitulina], and ribbon seals [Phoca fasciata]) caught in the Northern Pacific was analyzed using ICP-MS to understand its accumulation and distribution. In northern fur seals, relatively high concentrations of vanadium were observed in the liver, hair, and bone. Ninety percent of the vanadium burden in the body was concentrated in these three tissues, which comprise <20% of total body weight. Hepatic vanadium concentrations in the four pinniped species were significantly correlated to age, although the levels varied with species. An increase in vanadium accumulation in the liver of northern fur seals was caused by an increase of retention in nuclei and mitochondria fraction in the cells. Vanadium concentrations in liver were significantly correlated with mercury, silver, and selenium concentrations in northern fur seals, Steller sea lions, and harbor seals.

Mycobacterium leprae DNA in daily using water as a possible source of leprosy infection

Some environmental factors were suspected to be sources of leprosy infection according to the results of total survey in the highly endemic villages in Indonesia. M. leprae DNA were detected by PCR from 21 out of 44 water sources used daily by villagers. Prevalence of leprosy among the people using PCR-positive water for bathing and washing was significantly higher than that among the people who used PCR-negative water. No significant difference in prevalence was, however, recognized in case of usage of negative or positive water for drinking. Water was regarded as a reservoir and infectious source of M. leprae. Transmission of leprosy through the contaminated water was strongly suggested by epidemiological analysis.

An epidemiological study on Mycobacterium leprae infection and prevalence of leprosy in endemic villages by molecular biological technique

One of the most important unsolved questions in epidemiology of leprosy is the highly uneven geographic distribution of the disease. There are many hyperendemic "pockets" in endemic countries. Little is known about the reasons why leprosy is hyperendemic in these areas. We conducted, therefore, a series of epidemiological studies on Mycobacterium leprae infection and prevalence of leprosy in North Maluku district, Maluku Province, Indonesia where leprosy is highly endemic. It was found that considerable number of general inhabitants are seropositive to various mycobacterial antigens and 27% of the villagers were carrying leprosy bacilli on their surface of nasal cavity. These results suggested the importance of M. leprae in the residential environment in infection of the leprosy bacillus and the resulting transmission of the disease. Based on these observations, we conclude that new preventive measures are essential for global elimination of leprosy in addition to early diagnosis and multidrug therapy (MDT).

Difference in Bgp-independent fusion activity among mouse hepatitis viruses

Mouse hepatitis virus (MHV) utilizes a mouse biliary glycoprotein (Bgp) as a receptor. Co-cultivation of MHV-nonpermissive hamster BHK cells devoid of mouse Bgp with mouse DBT cells infected with MHV-A59 or JHMV induces syncytia formation on BHK cells (Bgp-independent fusion). This study shows the difference in Bgp-independent fusion activity among various MHV strains. Under a phase contrast microscopy, JHMV (cl-2, sp-4) induced the Bgp-independent syncytia on BHK cells similar to those observed on DBT cells, while such syncytia were not seen with the infection of other MHV strains (MHV-1, MHV-3, MHV-A59, MHV-S, srr7, srr11 and srr18). Tiny syncytia detectable only by immunofluorescence were produced with the latter MHV strains except for srr7 which failed to produce syncytia. MHVs except for srr7 grew in BHK cells after Bgp-independent infection. The Bgp-independent fusion by JHMV was inhibited either by anti-S1 or anti-S2 antibodies. These results showed that the JHMV spike protein had a remarkably high Bgp-independent fusion activity.

Tyrosine phosphorylation of proteins in primary human myeloid leukemia cells stimulated by cytokines: analysis of the frequency of phosphorylation, and partial identification and semi-quantification of signaling molecules

We investigated tyrosine phosphorylation of proteins in primary human leukemia cells stimulated by granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage CSF (GM-CSF), interleukin-3 (IL-3), tumor necrosis factor (TNF), thrombopoietin (TPO) and phorbol myristate acetate (PMA) in 61 patients with acute myeloid leukemia (AML), nine patients with chronic myeloid leukemia (CML) in blastic crisis and four patients in chronic phase, and compared these data of leukemia with those of normal human immature hematopoietic cells. These cytokines and PMA induced tyrosine phosphorylation of proteins in a manner characteristic for each cytokine or PMA in AML cells. G-CSF, GM-CSF and IL-3 frequently phosphorylated p92, p80, p70, p44 and p42. p95 was frequently phosphorylated by G-CSF, and was phosphorylated in one third of the cases by TPO. On the other hand, TNF selectively induced tyrosine phosphorylation of p42, and PMA selectively induced that of p44 and p42. In marked contrast to AML cells, CML cells responded poorly to cytokines with protein tyrosine phosphorylation, and normal human bone marrow mononuclear cells and CD34-positive cells also showed poor response to cytokines. The results of the immunoprecipitation studies showed tyrosine phosphorylation of signal transducers and activators of transcription (Stat) 5 induced by G-CSF, GM-CSF, IL-3 and/or TPO in six cases, that of extracellular signal-regulated kinase (ERK) by GM-CSF in two cases and that of p38 by TNF in three cases. Intracellular amount of Stat5 was markedly increased in AML cells compared with that in CML cells and normal human bone marrow cells. whereas intracellular amount of ERK and p38 was uniformly abundant in both leukemic and normal cells. These results show cytokine-specific and amplified tyrosine phosphorylation of proteins in AML cells and suggest that amplified response might, at least in part, result from the increased amount of signaling molecules such as Stat5.

The expression and localization of serine proteinase inhibitor PI-6 mRNA in developmental and ischemic mouse brain

A serine proteinase inhibitor, PI-6, is a member of the serine proteinase inhibitor (serpin) superfamily. In the present study, we investigated the developmental expression of PI-6 in the mouse brain and the effect of experimental ischemia on the expression of PI-6 in the adult brain. Northern blot analysis showed a high level of expression of PI-6 mRNA in brain stem and diencephalon as compared with other regions in the adult brain. The expression of PI-6 mRNA in the whole brain was increased gradually until 11 days after birth and was decreased again in the adult brain. In situ hybridization analysis revealed that the mRNA was localized in pyramidal cell layer of the post-natal hippocampus, especially in CA3 region, and in layer V of the cerebral cortex. In the brain stem, two specific motor nuclei, the facial nucleus and the motor nucleus of trigeminal nerve, which are important to active feeding, were strongly positive for PI-6 mRNA. Brain ischemia induced by bilateral ligation of the common carotid artery led to an increase in PI-6 mRNA expression in the whole brain, accompanied by the degeneration of hippocampal pyramidal cells. These results indicate distinct temporal and spatial expression of PI-6 in the mouse brain and suggest the involvement of PI-6 in the maturation of neurons and degenerative and regenerative processes.

[Present situation of leprosy in highly endemic area of tropical Asia--a seroepidemiological study of Mycobacterium leprae infection in general inhabitants]

One of the most important unsolved problems in epidemiology of leprosy is the heterogeneous geographic distribution of the disease. There are highly endemic area called "Pocket" in the endemic countries. Little is known why leprosy is so endemic in the area. We conducted, therefore, an epidemiological study on M. leprae infection and distribution of leprosy bacilli in the environment by using serological and molecular biological techniques. It was found that considerable number of general inhabitants in the pocket are infected with leprosy bacilli and more than 20% of the villagers are carrying M. leprae on the surface of the nasal cavity; suggesting that leprosy bacilli in the residential environment play an important role in high prevalence of leprosy in the endemic area. New preventive measures such as chemoprophylaxis, in addition to MDT, will be needed for global elimination of the disease.

Differential receptor-functionality of the two distinct receptor proteins for mouse hepatitis virus

We compared the virus-binding activity and receptor-functionality of the receptor proteins isolated from mouse hepatitis virus (MHV)-susceptible BALB/c mice (MHVR1) and MHV-resistant SJL mice (MHVR2). By using a soluble receptor protein which lacked the transmembrane and intracytoplasmic domains, virus overlay protein blot assay and neutralization tests showed that MHVR1 bound to JHM cl-2 virus with 300-500 times higher efficiency than to MHVR2. MHVR1 was revealed to have 10-30 fold higher receptor-functionality than MHVR2 when examined by measuring virus-binding to the receptor expressed on the cell surface. These findings suggested that the differences in susceptibility between BALB/c and SJL mice may depend upon the genotype of the MHV receptor.

Isolation and characterization of murine coronavirus mutants resistant to neutralization by soluble receptors

Murine coronavirus mutants resistant to neutralization with soluble receptors were isolated to study the receptor-binding site on the S proteins since such mutants were expected to have mutations in an important site for receptor-binding. We have isolated five soluble receptor-resistant (srr) mutants which had mutations of a single amino acid at 3 different positions in S protein. Srr mutant 11 with an amino acid change at position 65 (Leu to His) in the S1 subunit showed an extremely reduced binding by virus overlay protein blot assay. However srr mutants with a mutation at 1114 (Leu to Phe) (srr mutants 3, 4 and 7) or 1163 (Cys to Phe) (srr mutant 18) in the S2 subunit had receptor-binding activity similar to that of wild type cl-2. These results suggest that an amino acid at position 62 located in a conserved region among MHV strains is in particular important for receptor binding. We also discuss why srr mutants with a mutation in S2 showed high resistance to neutralization by soluble receptor, irrespective of their binding to MHV receptors.

Cooperative stimulatory effects of tumor necrosis factor and granulocyte-macrophage colony-stimulating factor on the particular respiratory burst activity in human neutrophils: synergistic priming effect on concanavalin A-induced response, no interactive priming effect on the chemotactic peptide-induced response and additive triggering effect

Tumor necrosis factor (TNF), granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) rapidly primed human neutrophils for enhanced superoxide (O2-) release, and membrane depolarization stimulated by chemotactic peptide (N-formyl-methionyl-leucyl-phenylalanine), interleukin 8, concanavalin A (Con A) and ionomycin. Combined stimulation of human neutrophils with the optimal concentrations of TNF plus GM-CSF showed no additive or synergistic effects according to the subsequent stimuli and within the parameters tested. Particularly, a high synergistic priming effect of these two cytokines was observed when Con A was used as a triggering agonist of O2- release. The priming of human neutrophils with the optimal concentrations of TNF plus G-CSF, however, always resulted in the same effect as TNF alone. TNF and GM-CSF triggered O2- release directly in human neutrophils for prolonged time periods, and combined stimulation of human neutrophils with the optimal concentrations of TNF plus GM-CSF triggered an added amount of O2- release. TNF and GM-CSF by themselves induced an increase in cytoplasmic pH (intracellular alkalinization), an important signaling event for functional activation of neutrophils, though combined stimulation of human neutrophils with the optimal concentrations of the two cytokines had no additive effects on cytoplasmic pH. The present results show cooperative interaction between TNF and GM-CSF in their stimulatory effects on particular functions in human neutrophils, and these synergistic effects are probably mediated via a mechanism distal to or independent of intracellular alkalinization.

Rapid production of fertile transgenic barley (Hordeum vulgare L.) by direct gene transfer to primary callus-derived protoplasts

Protoplasts were isolated from primary calli of barley (Hordeum vulgare L.), and an antibiotic (G418) resistance gene was introduced into these protoplasts using a polyethylene glycol (PEG) DNA uptake method. Sixty-four G418 resistant calli were obtained in nine experiments, and two plants were regenerated from these calli. NPTII ELISA and Southern analysis indicated that the G418 resistance gene was introduced and expressed in two T₀ plants. These plants set seed and the introduced gene was transmitted to T₁ plants. These results suggest that our transformation system using primary callus-derived protoplasts is a useful method for the generation of transgenic barley.

Enzymatic properties of a novel liquefying alpha-amylase from an alkaliphilic Bacillus isolate and entire nucleotide and amino acid sequences

A novel liquefying alpha-amylase (LAMY) was found in cultures of an alkaliphilic Bacillus isolate, KSM-1378. The specific activity of purified LAMY was approximately 5,000 U mg of protein-1, a value two- to fivefold greater between pH 5 and 10 than that of an industrial, thermostable Bacillus licheniformis enzyme. The enzyme had a pH optimum of 8.0 to 8.5 and displayed maximum activity at 55 degreesC. The molecular mass deduced from sodium dodecyl sulfate-polyacrylamide gel electrophoresis was approximately 53 kDa, and the apparent isoelectric point was around pH 9. This enzyme efficiently hydrolyzed various carbohydrates to yield maltotriose, maltopentaose, maltohexaose, and maltose as major end products after completion of the reaction. Maltooligosaccharides in the maltose-to-maltopentaose range were unhydrolyzable by the enzyme. The structural gene for LAMY contained a single open reading frame 1, 548 bp in length, corresponding to 516 amino acids that included a signal peptide of 31 amino acids. The calculated molecular mass of the extracellular mature enzyme was 55,391 Da. LAMY exhibited relatively low amino acid identity to other liquefying amylases, such as the enzymes from B. licheniformis (68.9%), Bacillus amyloliquefaciens (66.7%), and Bacillus stearothermophilus (68.6%). The four conserved regions, designated I, II, III, and IV, and the putative catalytic triad were found in the deduced amino acid sequence of LAMY. Essentially, the sequence of LAMY was consistent with the tertiary structures of reported amylolytic enzymes, which are composed of domains A, B, and C and which include the well-known (alpha/beta)8 barrel motif in domain A.

Characterization of brain-type ryanodine receptor permanently expressed in Chinese hamster ovary cells

To clarify a function of brain-type ryanodine receptor (RyR3) and its regulation, we established a stable cell line expressing rabbit RyR3 by transfection of Chinese hamster ovary cells (CHO cells) with the cDNA and investigated characteristics of the RyR3. Scatchard analysis of [3H]-ryanodine binding to the membrane from CHO cells expressing RyR3 showed two distinct binding sites. The Kd values of high and low affinity binding sites were 1.92 and 25.9 nM, respectively. [3H]-ryanodine binding to the membrane from CHO cells expressing RyR3 was dependent on pCa. Extracellular Ca2+ (2-10 mM) and high concentration (more than 30 mM) of caffeine activated the RyR3 in CHO cells and increased its intracellular Ca2+ concentration. The enhancement of [3H]-ryanodine binding to the membrane from CHO cells expressing RyR3 was observed by bromoeudistomin D (BED), a caffeine-like powerful Ca2+ releaser, at pCa 5.5. Stably expressed RyR3 in CHO is useful for characterization of its function.

Sequence analysis and expression of a novel mouse homolog of Escherichia coli recA gene

Escherichia coli recA and its yeast homologs RAD51 and DMC1 play crucial roles in mitotic and/or meiotic recombination and in repair of double-strand DNA breaks. We have identified a murine novel recA-like gene (MmTRAD). The predicted 329 amino acid protein showed significant homology to mouse Rec2, Rad51, Dmc1 (or Lim15) and E. coli RecA. Northern blot analysis revealed that MmTRAD was ubiquitously transcribed in various tissues.