Mol Cell+iSciecne Jixiong's team revealed RNA polymerase II subunit heteroplasmism and CTCF insulation mechanism

On September 15, 2022, Ji Xiong's research group at the Center for Life Sciences and the School of Life Sciences of Peking University published a research paper

RNA polymerase II, which is primarily responsible for the transcription of protein-coding genes, is a protein complex consisting of 12 subunits

The researchers first established a transiently degraded cell line of 12 subunits of RNA polymerase II in mouse embryonic stem cells, and the chromatin genome and proteome were quantified by chromatin interaction genomic sites and proteins

Next, the researchers used the neonatal RNA sequencing experiment (PRO-Seq) to explore the effect

To further confirm the above conjecture, the researchers conducted PolyA-RNA-Seq experiments after long-term degradation (12h) to explore the effects of each subunit on the mature mRNAs of

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PolyA-RNA-Seq experimental results also show that some subunits can lead to different degrees of expression upregulation of some genes, and the researchers analyzed that gene upregulation may be caused by the imbalance of the post-transcriptional process, such as transcript 3' end processing defects, splicing processing defects, etc

Figure 2.

In the RNA polymerase subunit work, Ji Xiong, a researcher at the School of Life Sciences of Peking University, is the corresponding author of the paper, and Dr.

On September 16, 2022, the Center for Life and Ji Xiong's research group of the School of Life Sciences of Peking University, together with the Center for Life and the Qi Zhi Group of the Center for Quantitative Biology, published a research paper entitled "CTCF DNA binding domain undergoes dynamic and selective protein–protein interactions" in iScience.

CTCF (CCCTC-binding factor) is the most important insulator-binding protein currently known in vertebrates, which can block the activation of the promoter by the enhancer, inhibit the expression of genes, and can also act as a "barrier" to prevent the spread

The researchers used the "optoDroplet" system of light-induced protein aggregation to screen the DNA-binding domain of CTCF to aggregate; In vitro, it was verified that the DBD of CTCF could aggregate to form dynamic droplets; Next, through protein colocalization analysis combined with live cell tracking imaging, the researchers found that the aggregation of CTCF DBD can recruit insulator-related proteins CHD8 and BRD2, and drain the transcriptional activator OCT4.

Figure 3.

In the work of CTCF insulation mechanism, Ji Xiong, a researcher at the Center for Life Sciences and the School of Life Sciences of Peking University, and Qi Zhi, a researcher at the Center for Life Sciences and the Center for Quantitative Biology, are the co-corresponding authors

Ji Xiong's research group has long been engaged in the study

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