Arginine methylation is a post-translational modification which is catalyzed by protein arginine methyltransferases (PRMTs). Here, we report that PRMT1 is highly expressed in neural stem/precursor cells (NS/PCs) of mouse embryos, and knockdown of PRMT1 in NS/PCs suppresses the generation of astrocytes. The luciferase assay demonstrated that knockdown of PRMT1 inhibits activation of the promoter of a typical astrocytic marker gene, glial fibrillary acidic protein (Gfap), in NS/PCs. The transcription factor signal transducer and activator of transcription 3 (STAT3) is known to generally be critical for astrocytic differentiation of NS/PCs. We found that PRMT1 methylates arginine residue(s) of STAT3 to regulate its activity positively, resulting in the promotion of astrocytic differentiation of NS/PCs.

In multicellular organisms, expression profiling in spatially defined regions is crucial to elucidate cell interactions and functions. Here, we establish a transcriptome profiling method coupled with photo-isolation chemistry (PIC) that allows the determination of expression profiles specifically from photo-irradiated regions of interest. PIC uses photo-caged oligodeoxynucleotides for in situ reverse transcription. PIC transcriptome analysis detects genes specifically expressed in small distinct areas of the mouse embryo. Photo-irradiation of single cells demonstrated that approximately 8,000 genes were detected with 7 × 104 unique read counts. Furthermore, PIC transcriptome analysis is applicable to the subcellular and subnuclear microstructures (stress granules and nuclear speckles, respectively), where hundreds of genes can be detected as being specifically localised. The spatial density of the read counts is higher than 100 per square micrometre. Thus, PIC enables high-depth transcriptome profiles to be determined from limited regions up to subcellular and subnuclear resolutions.

documented in the adult liver in some animal models. [5][6][7][8] Oval The sarcomatoid cells found in cholangiocarcinoma (CC) cells are generally believed to be an expanding progenitor or hepatocellular carcinoma (HCC) are not well characterized.cell population derived from terminal biliary ductules, 9,10 and In this study, a human sarcomatoid CC cell line, ETK-1, was are capable of differentiating into hepatocytes, [10][11][12][13][14][15] HCC. The ETK-1 cells appeared to be converted into hepato-Our objective was to establish a line of human CC cells cytes by exposure to 5-azaCR. On the other hand, ETK-1 xenofrom the sarcomatoid component of CC. The successfully grafts were diagnosed as tubular adenocarcinoma, and the established cell line, designated as ETK-1, was characterized tumor cells had a ductal phenotype. This suggests the possibiland examined for morphological and phenotypical converity that ETK-1 cells can differentiate along a biliary epithelial sion after treatment with the differentiation-inducing recell lineage. ETK-1 and MEK will be useful in studying hepatoagent, 5-azacytidine (5-azaCR). for 24 hours and washed with MA medium to remove nonadherent

Sarcomatous transformation is found in approximately 5% of patients with intrahepatic cholangiocarcinoma. According to previous reports, sarcomatous cholangiocarcinomas are composed of spindle-shaped cells and/or multinucleated giant cells. Usually, vimentin is expressed by these sarcomatoid cells. We report a case of intrahepatic cholangiocarcinoma with an element of rhabdoid cells that occurred in a 61-year-old woman admitted for back pain. Various imaging techniques demonstrated multiple liver masses. Histologically, these tumours formed in both sarcomatous and ordinary tubular adenocarcinomatous areas. The sarcomatoid areas were occupied mainly by loosely arranged, eosinophilic rhabdoid cells, which expressed both keratin and vimentin. These findings suggest that rhabdoid cells may occur in an undifferentiated stage of cholangiocarcinoma and possess a strong tendency to metastasize.