The team of Dong Xiuzhu, Institute of Microbiology, Chinese Academy of Sciences discovered the mechanism of transcription termination in archaea

Archaea, a third life form distinct from bacteria and eukaryotes, have bacterial-like cellular forms but use eukaryotic-like genetic information transfer machinery
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Because archaea were discovered and established as an independent life domain later than bacteria and eukaryotes, and most of them belong to extremophiles, their biological processes and genetic mechanisms are poorly understood
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Transcription termination is an important biological process that defines the 3' end of a transcript and its correct structure to ensure the correct transmission of genetic information stored in DNA
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Defects in transcription termination will lead to disorder of transcriptome expression, dysregulation of gene expression, and chromosomal breakage due to collisions between biological macromolecular machines
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Therefore, the mechanism of transcription termination in bacteria and eukaryotes has been intensively studied internationally, but little is known about the process and mechanism of transcription termination in archaea
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The research group of Dong Xiuzhu, Institute of Microbiology, Chinese Academy of Sciences has been devoted to the research on the physiological metabolism and environmental adaptation mechanism of the most widely distributed and most abundant archaea in nature for many years
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After more than 10 years of research, the research team led by Dr.
Li Jie in Dong Xiuzhu's team discovered the mRNA processing phenomenon at the omics level in model methanogens, which changed the previous perception that prokaryotes "mRNA does not process" and revealed that archaea The post-transcriptional regulation mechanism of ribosomal protein synthesis and assembly (Nucleic Acids Res, 2017); found that mRNA processing is important for low temperature adaptation in Methanogens (Environ Microbiol, 2021), and revealed the working mechanism of related nucleases (RNA Biol 2020; MolMicrobiol, 2017); discovered the first archaeal cold shock protein and its RNA chaperone function (PLoS Genet, 2019; Front Microbiol, 2017)
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Recently, the research group has reported a global transcription termination factor-endonuclease aCPSF1, which has been searched for nearly 40 years in archaea, through systematic research for nearly 6 years, revealing that aCPSF1 mediated by cutting the 3′ end of RNA.
The working mode of transcription termination in archaea - similar to the transcription termination mode of eukaryotic RNA polymerase II, provides new genetic evidence for "archaea are the evolutionary origin of eukaryotes"
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aCPSF1 is widely distributed in all archaea, and aCPSF1 of distantly related archaea and Asgard also plays a transcription termination function in methanogens, indicating that archaea widely adopt aCPSF1-dependent transcription termination mode
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The findings were published in Nucleic Acids Res (2020)
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In cooperation with Dr.
Xiaowei Zheng from the research group of Li Huang, the research team found that the aCPSF1 protein is a new phylogenetic molecular marker of archaea, which can be used for taxonomic research of archaea
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The archaeal aCPSF1 classification system has a higher resolution than 16S rRNA, and avoids the time-consuming problems of currently employed genome phylogenetic analysis
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The findings were published in Microbiology Spectrum (2021)
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Archaeal aCPSF1 transcription termination mode is a nascent and simplified version of eukaryotic RNA polymerase II transcription termination.
The U-tract sequence at the 3' end of the terminator signal specifically recognized by the termination factor aCPSF1 was proved, and it was found that aCPSF1 relies on its N-terminal KH domain to specifically recognize the terminator signal and its nuclease domain to complete the cleavage of the 3' end of mRNA Thus mediating efficient termination of archaea
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It is thus found that in archaea, the transcription termination factor aCPSF1 (trans-acting protein) cooperates with the terminator U-tract sequence (cis element) to control efficient transcription termination efficiency, which is significantly different from bacteria; Bacteria adopt a eukaryotic-like transcription termination mode, but its transcription termination mode should be a nascent and simplified version of eukaryotic transcription termination
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The results were published online in eLife on December 30
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Associate researcher Li Jie, doctoral student Yue Lei and master student Li Zhihua are the co-first authors of the paper, and researcher Dong Xiuzhu and associate researcher Li Jie are the co-corresponding authors; the research work has been supported by the National Natural Science Foundation of China, the National Key R&D Program and other projects financial support
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Links to related papers: https://academic.
oup.
com/nar/article/48/17/9589/5898609https://elifesciences.
org/articles/70464https://journals.
asm.
org/doi/10.
1128/spectrum.
01539-21 (Note: the cover is a schematic diagram, from the Internet)