In the afternoon of October 16, 2020, Professor Shen Xiaohua from the School of Medicine, Tsinghua University, gave a wonderful academic seminar entitled A glimpse of the noncoding portions of the genome in transcription and chromatin regulation for the teachers and students of our school, with much unpublished data.
First, Prof. Shen gave some introduction of the background for her research interest. In animals including humans, the DNA sequences of the coding genes only account for a small part of the genome sequence, whereas the majority of the genomic DNA sequence is comprised of repetitive sequences such as LINE1 and SINE. It is difficult to fully explain a series of complex life processes such as differentiation and apoptosis in higher animals with a limited number of genes. Therefore, Prof. Shen believes that repetitive sequences play an important role in chromosome regulation. Prof. Shen elaborated her research work from three following areas: IncRNA, RNA binding proteins, and DNA repeat sequences.
By using ES cells as a model system, Prof. Shen studied the effects of IncRNA on the activation and silencing of some genes in the cells. The IncRNAs in Cis regulation on adjacent genes usually are short lived and depend on U1 snRNA. By contrast, lncRNAs in trans regulation tend to be more abundant and more stable. Professor Shen also used proteomics technology to discover some new RNA binding proteins. In addition, Professor Shen showed us the important relationship between DNA repeat sequences and chromosome three-dimensional structure through ChIP and bioinformatics approaches. In particular, LINE1 repeats and B1 repeats are located on different compartments at least partly through homotypic clustering of LINE1 repeats. Knocking down LINE1 by AMO disrupts chromosomal segregation of LINE1 and B1 repeats.
Mr. Shen's wonderful speech had won great applause from us. Quite a few teachers and students asked some good questions after her talk. Prof. Shen patiently answered all raised questions and explained the results in detail. The seminar ended successfully following these good discussions.
