Transgenic mouse model of cutaneous adnexal tumors

TMEM207 was first characterized as being an important molecule for the invasion activity of gastric signet-ring cell carcinoma cells. In order to unravel the pathological properties of TMEM207, we generated several transgenic mouse lines, designated C57BL/6-Tg (ITF-TMEM207), in which murine TMEM207 was ectopically expressed under a truncated (by ~200 bp) proximal promoter of the murine intestinal trefoil factor (ITF) gene (also known as Tff3). Unexpectedly, a C57BL/6-Tg (ITF-TMEM207) mouse line exhibited a high incidence of spontaneous intradermal tumors with histopathological features that resembled those of various human cutaneous adnexal tumors. These tumors were found in ~14% female and 13% of male 6- to 12-month-old mice. TMEM207 immunoreactivity was found in hair follicle bulge cells in non-tumorous skin, as well as in cutaneous adnexal tumors of the transgenic mouse. The ITF-TMEM207 construct in this line appeared to be inserted to a major satellite repeat sequence at chromosome 2, in which no definite coding molecule was found. In addition, we also observed cutaneous adnexal tumors in three other C57BL/6-Tg (ITF-TMEM207) transgenic mouse lines. We believe that the C57BL/6-Tg (ITF-TMEM207) mouse might be a useful model to understand human cutaneous adnexal tumors.KEY WORDS: Cutaneous adnexal tumor, Mouse model, TMEM207     

Remodeling of the Rad51 DNA Strand-Exchange Protein by the Srs2 Helicase

Homologous recombination is associated with the dynamic assembly and disassembly of DNA–protein complexes. Assembly of a nucleoprotein filament comprising ssDNA and the RecA homolog, Rad51, is a key step required for homology search during recombination. The budding yeast Srs2 DNA translocase is known to dismantle Rad51 filament in vitro. However, there is limited evidence to support the dismantling activity of Srs2 in vivo. Here, we show that Srs2 indeed disrupts Rad51-containing complexes from chromosomes during meiosis. Overexpression of Srs2 during the meiotic prophase impairs meiotic recombination and removes Rad51 from meiotic chromosomes. This dismantling activity is specific for Rad51, as Srs2 Overexpression does not remove Dmc1 (a meiosis-specific Rad51 homolog), Rad52 (a Rad51 mediator), or replication protein A (RPA; a single-stranded DNA-binding protein). Rather, RPA replaces Rad51 under these conditions. A mutant Srs2 lacking helicase activity cannot remove Rad51 from meiotic chromosomes. Interestingly, the Rad51-binding domain of Srs2, which is critical for Rad51-dismantling activity in vitro, is not essential for this activity in vivo. Our results suggest that a precise level of Srs2, in the form of the Srs2 translocase, is required to appropriately regulate the Rad51 nucleoprotein filament dynamics during meiosis.     

Sleep disturbance is associated with not only shorter sleep duration,but also longer time in bed: a Japanese general population survey

Sleep and Biological Rhythms - Individuals with chronic insomnia tend to increase their amount of time in bed (TIB) to secure more opportunity for sleep, which in turn, may aggravate and perpetuate...     

Glycolytic intermediates induce amorphous calcium carbonate formation in crustaceans

It has been thought that phosphorus in biominerals made of amorphous calcium carbonate (ACC) might be related to ACC formation, but no such phosphorus-containing compounds have ever been identified. Crustaceans use ACC biominerals in exoskeleton and gastroliths so that they will have easy access to calcium carbonate inside the body before and after molting. We have identified phosphoenolpyruvate and 3-phosphoglycerate, intermediates of the glycolytic pathway, in exoskeleton and gastroliths and found them important for stabilizing ACC.     

Detection of Merkel cell polyomavirus in cervical squamous cell carcinomas and adenocarcinomas from Japanese patients

ABSTRACT: BACKGROUND: Merkel cell polyomavirus (MCPyV) was identified originally in Merkel cell carcinoma (MCC), a rare form of human skin neuroendocrine carcinoma. Evidence of MCPyV existence in other forms of malignancy such as cutaneous squamous cell carcinomas (SCCs) is growing. Cervical cancers became the focus of our interest in searching for potentially MCPyV-related tumors because: (i) the major histological type of cervical cancer is the SCC; (ii) the uterine cervix is a common site of neuroendocrine carcinomas histologically similar to MCCs; and (iii) MCPyV might be transmitted during sexual interaction as demonstrated for human papillomavirus (HPV). In this study, we aimed to clarify the possible presence of MCPyV in cervical SCCs from Japanese patients. Cervical adenocarcinomas (ACs) were also studied. RESULTS: Formalin-fixed paraffin-embedded tissue samples from 48 cervical SCCs and 16 cervical ACs were examined for the presence of the MCPyV genome by polymerase chain reaction (PCR) and sequencing analyses. PCR analysis revealed that 9/48 cervical SCCs (19 %) and 4/16 cervical ACs (25 %) were positive for MCPyV DNA. MCPyV-specific PCR products were sequenced to compare them with reference sequences. The nucleotide sequences in the MCPyV large-T (LT)-sequenced region were the same among MCPyV-positive cervical SCCs and AC. Conversely, in the MCPyV viral protein 1 (VP1)-sequenced, two cervical SCCs and three cervical ACs showed several nucleotide substitutions, of which three caused amino acid substitutions. These sequencing results suggested that three MCPyV variants of the VP1 were identified in our cases. Immunohistochemistry showed that the LT antigen was expressed in tumor cells in MCPyV-positive samples. Genotyping of human HPV in the MCPyV-positive samples revealed that infected HPVs were HPV types 16, 31 and 58 for SCCs and HPV types 16 and 18 for ACs. CONCLUSIONS: This study provides the first observation that MCPyV coexists in a subset of HPV-associated cervical cancers from Japanese patients. The prevalence of MCPyV in these lesions was close to that observed in the cutaneous SCCs. Further worldwide epidemiological surveys are warranted to determine the possible association of MCPyV with pathogenesis of cervical cancers.     

Isolation of transposon Tn5 mutant affected in the metabolism of 18β-glycyrrhetinic acid

Transposon Tn5 mutagenesis was carried out to clarify the metabolism of 18-glycyrrhetinic acid (18-GRA) in Sphingomonas paucimobilis G5. A Tn5-induced mutant strain, named TM9638 that was affected in its metabolism of 18-GRA, was isolated. This mutant accumulated three metabolites, designated as M-A, M-B and M-C, from 18-GRA in the culture broth. M-A was accumulated in the culture broth of wild type strain, but M-B and M-C were not accumulated in the culture broth of wild type strain. M-B and M-C were isolated from the culture broth of TM9638 and the chemical structures were elucidated by NMR and GC-MS.     

Metabolism of 18β-glycyrrhetinic acid in Sphingomonas paucimobilis strain G5

Seven strains capable of utilizing 18-glycyrrhetinic acid (18-GRA) as a sole carbon and energy source were isolated from soil samples by enrichment culture technique. One of these strains, named strain G5, was identified as Sphingomonas paucimobilis. When this strain grew on 18-GRA, several metabolites were detected in the culture broth. A major metabolite, tentatively named M-A, was isolated and its chemical structure was determined by nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GC-MS).     

Identification of novel metabolites in the degradation of phenanthrene by Sphingomonas sp. strain P2

Sphingomonas sp. strain P2, which is capable of utilizing phenanthrene as a sole carbon and energy source, was isolated from petroleum-contaminated soil in Thailand. Gas chromatography-mass spectrometry and (1)H and (13)C nuclear magnetic resonance analyses revealed two novel metabolites from the phenanthrene degradation pathway. One was identified as 5,6-benzocoumarin, which was derived by dioxygenation at the 1- and 2-positions of phenanthrene, and the other was determined to be 1,5-dihydroxy-2-naphthoic acid. Other metabolites from phenanthrene degradation were identified as 7, 8-benzocoumarin, 1-hydroxy-2-naphthoic acid and coumarin. From these results, it is suggested that strain P2 can degrade phenanthrene via dioxygenation at both 1,2- and 3,4-positions followed by meta-cleavage.     

Hypomethylation and expression of pepsinogen A genes in the fundic mucosa of human stomach

We have examined the correlation between the extents of methylation and expression of pepsinogen A genes in normal human tissues. Expression of pepsinogen A mRNA was detected only in the fundic mucosa of the stomach and both CCGG and GCGC sites in the genes region were less methylated in the fundic mucosa than in other non-expressing tissues. Thus, there was an inverse correlation between the extents of methylation and expression of pepsinogen A genes and the role of DNA methylation in the regulation of pepsinogen A genes expression during normal differentiation was suggested.     

Kinetic Characterization of Two Phosphate Uptake Systems with Different Affinities in Suspension-Cultured Catharanthus roseus Protoplasts

We studied the kinetics of inorganic phosphate (P₁) uptake from0.1–1,000 µM P₁ by protoplasts from suspension-culturedcells of Catharanthus roseus (L.) G. Don. Concentration dependenceof [³²P]P₁ uptake revealed two kinetically different uptakesystems, a high-affinity system and a low-affinity system, withK_m values of 3.0 and 47 µM, respectively. Protoplastsfrom cells grown in P_i-rich media had a medium level of thelow-affinity activity and a very low level of the high-affinityactivity. It appeared low-affinity system is expressed constitutively,while the high-affinity system is regulated by the availabilityof P_i. When cells grown in a P_i-rich media were transferredto P_i-depleted media, the high-affinity activity increased significantlyafter 2 d, but the low-affinity activity was barely changed.Upon addition of 10 mM P_i, the high level of the high-affinityactivity fell to almost undetectable level in 1d. Both uptakesystems exhibited maximum activity between pH 5 and 6. ¹ Present address: Tokyo Research Laboratories, Kyowa HakkoKogyo Co., Ltd., 3-6-6 Asahi-cho, Machida, Tokyo, 194 Japan.