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Heightened interest in relevant models for human disease increases the need for improved methods for germline transgenesis. We describe a significant improvement in the creation of transgenic laboratory mice and rats by chemical modification of Sleeping Beauty transposons. Germline transgenesis in mice and rats was significantly enhanced by in vitro cytosine-phosphodiester-guanine methylation of transposons prior to injection. Heritability of transgene alleles was also greater from founder mice generated with methylated versus non-methylated transposon. The artificial methylation was reprogrammed in the early embryo, leading to founders that express the transgenes. We also noted differences in transgene insertion number and structure (single-insert versus concatemer) based on the influence of methylation and plasmid conformation (linear versus supercoiled), with supercoiled substrate resulting in efficient transpositional transgenesis (TnT) with near elimination of concatemer insertion. Combined, these substrate modifications resulted in increases in both the frequency of transgenic founders and the number of transgenes per founder, significantly elevating the number of potential transgenic lines. Given its simplicity, versatility and high efficiency, TnT with enhanced Sleeping Beauty components represents a compelling non-viral approach to modifying the mammalian germline. [ABSTRACT FROM AUTHOR]

New chiral banana‐shaped liquid crystals with chiral 3‐(alkoxy)propoxy terminal groups (P n ‐O‐PIMB5*‐4O, n = 7, 8, 9 and 10) were synthesized and their mesomorphic properties and phase structures investigated by means of electro‐optic measurements, polarizing optical microscopy, differential scanning calorimetry, and second harmonic generation measurements. Most of these chiral bent‐core mesogens ( n = 7–9) showed the antiferroelectric B2 phase, whereas P10‐O‐PIMB5*‐4O exhibited the B7 phase. Comparing with the previously reported homologue P n ‐O‐PIMB( n ‐2)*, we conclude that the terminal chain structure, particularly the position of chiral centres, plays an important role in the emergence of particular phase structures. [ABSTRACT FROM AUTHOR]

We previously reported that the mouse Copg2 (Coatomer Protein Subunit Gamma 2) gene was imprinted in the intraspecific F1 hybrid mice between C57BL/6 and M. m. molossinus. In this study, methylation status at the promoter-associated CpG island and allele-specific expression pattern of Copg2 were investigated in the interspecific F1 hybrid (C57BL/6 ⊗ M. spretus). We found that Copg2 was biallelically expressed in the interspecific F1 hybrid, despite the presence of a differentially methylated region (DMR) in the CpG island. Therefore, paternal-specific methylation at the CpG island of Copg2 is not accompanied by allele-specific expression of Copg2 in the F1 hybrid (C57BL/6 ⊗ M. spretus). The results suggest that the imprinted pattern of Copg2 expression is subject to variable epigenetic control systems of different mouse species. In addition, we identified a novel antisense transcript, Copg2AS2, at the Copg2 promoter region. The antisense transcript was expressed monoallelically, indicating that the differential expression of the antisense transcript is correlated with the differential methylation at the CpG island of Copg2. [ABSTRACT FROM AUTHOR]