Heterologous survey of 130 DNA transposons in human cells highlights their functional divergence and expands the genome engineering toolbox.

Experimental studies on DNA transposable elements (TEs) have been limited in scale, leading to a lack of understanding of the factors influencing transposition activity, evolutionary dynamics, and application potential as genome engineering tools. We predicted 130 active DNA TEs from 102 metazoan genomes and evaluated their activity in human cells. We identified 40 active (integration-competent) TEs, surpassing the cumulative number (20) of TEs found previously. With this unified comparative data, we found that the Tc1/mariner superfamily exhibits elevated activity, potentially explaining their pervasive horizontal transfers. Further functional characterization of TEs revealed additional divergence in features such as insertion bias. Remarkably, in CAR-T therapy for hematological and solid tumors, Mariner2_AG (MAG), the most active DNA TE identified, largely outperformed two widely used vectors, the lentiviral vector and the TE-based vector SB100X. Overall, this study highlights the varied transposition features and evolutionary dynamics of DNA TEs and increases the TE toolbox diversity.

Structural RNA components supervise the sequential DNA cleavage in R2 retrotransposon.

Retroelements are the widespread jumping elements considered as major drivers for genome evolution, which can also be repurposed as gene-editing tools. Here, we determine the cryo-EM structures of eukaryotic R2 retrotransposon with ribosomal DNA target and regulatory RNAs. Combined with biochemical and sequencing analysis, we reveal two essential DNA regions, Drr and Dcr, required for recognition and cleavage. The association of 3' regulatory RNA with R2 protein accelerates the first-strand cleavage, blocks the second-strand cleavage, and initiates the reverse transcription starting from the 3'-tail. Removing 3' regulatory RNA by reverse transcription allows the association of 5' regulatory RNA and initiates the second-strand cleavage. Taken together, our work explains the DNA recognition and RNA supervised sequential retrotransposition mechanisms by R2 machinery, providing insights into the retrotransposon and application reprogramming.

[Application of metabolomics approach to study of different parts of Mountain Cultivated Ginseng using UHPLC-QTOF/MS].

In present study, an ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UHPLC-QTOF/MS)-based plant metabolomics approach was established to investigate the metabolic profiles of the leaves, main root, branch root, and rhizome of Mountain Cultivated Ginseng (MCG). The UHPLC-QTOF/MS data were subjected to principal component analysis(PCA) and orthogonal partial least squared discrimination analysis(OPLS-DA) to find the potential characteristic components of the four parts of MCG in a quick way. The four different parts could be separated into four different groups of phytochemicals according to the PCA scores. The chemical constituents in four parts of MCG were obviously different. The identities of 81 major peaks that were detected in the four parts of MCG and the potential markers were identified by comparison with the reference compounds or were tentatively assigned by matching the retention time, empirical molecular formula and fragment ions with those of the published compounds of the Panax species. This proposed analytical method is fast, accurate, and reliable for differentiating the different parts of MCG. Moreover, this study supplied a new method for the quality evaluation of other Chinese medicinal materials.