In embryonic stem cells (ESCs), the expression of development-related genes, including germ cell–related genes, is globally repressed. The transcription factor MAX represses germ cell–related gene expression in ESCs via PCGF6-polycomb repressive complex 1 (PRC1), which consists of several epigenetic factors. However, we predicted that MAX represses germ cell–related gene expression through several additional mechanisms because PCGF6-PRC1 regulates the expression of only a subset of genes repressed by MAX. Here, we report that MAX associated with DNA methyltransferases (DNMTs) and the histone methyltransferase SETDB1 cooperatively control germ cell–related gene expression in ESCs. Both DNA methylation and histone H3 lysine 9 tri-methylation of the promoter regions of several germ cell–related genes were not affected by knockout of the PRC1 components, indicating that the MAX-DNMT and MAX-SETDB1 pathways are independent of the PCGF6-PRC1 pathway. Our findings provide insights into our understanding of MAX-based repressive mechanisms of germ cell–related genes in ESCs.

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Surface properties of Au electrodes modified by benzenethiol derivatives with a fluorine atom(s) have been methodically researched based on measurements of the work function and the contact angles. Benzenethiol derivatives with a fluorine atom(s) at ortho, meta, and/or para position were used for modification in this work. The measured work function was in a relatively wide range between 4.24-6.02 eV. The work function change from a bare Au surface was explained on the principle of dipole moments obtained by quantum chemical calculation. The water contact angle was found to vary between 64.8°and 97.7°. Furthermore, the surface tension was calculated from the measured contact angles of water and ethylene glycol. The calculated surface tension was reviewed from the perspective of the position of the substitute in the benzenethiol derivative. In addition, organic thinfilm transistors (TFTs) with drain and source electrodes modified with 2-fluorobenzenethiol (2-FBT), 3-fluorobenzenethiol (3-FBT) or pentafluorobenzenethiol (PFBT) were characterized as other evaluations of the modified Au surface. The contact resistance in the TFT increased in the order of PFBT, 3-FBT and 2-FBT. The increase of the contact resistance was consistent with the decrease in the work function.

The thin-films of 2,9-diphenyl-dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DPh-DNTT) prepared by vacuum deposition was observed by the optical microsope. By applying the dark-field mode in observation and/or image processing after imaging appropriately, morphological structure with a resolution of a few nanometers height was visualized easily and quickly. The technique can be used in a similar to atomic force microscopy, which is commonly used for imaging surface morphology. Moreover, the vibrational modes of a DPh-DNTT molecule calculated by quantum chemistry program is described as well as the comparison of the experimental Raman spectra for identification. The presented data are produced as part of the main work entitled “The Growth Mechanism and Characterization of Few-layer Diphenyl Dinaphthothienothiophene Films Prepared by Vacuum Deposition” (Hattori et al., 2019).

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