Interpreting the "Book of Life": Chinese Scientists Fill the Gap in the Research of Chloroplast Gene "Transcription Machine".
In a recent study, Chinese scientists have successfully analyzed the structure of the "transcription machine" of chloroplast genes, filling a research gap in the "Book of Life".
On March 1, the international academic journal "Cell" published the study completed by Zhang Yu's research team from the Center for Excellence in Molecular Plant Science of the Chinese Academy of Sciences and Zhou Fei's research team at Huazhong Agricultural University.
The complex structure of chloroplast PEP, the "transcription machine" of chloroplast genes. (Photo courtesy of the Center for Excellence in Molecular Plant Science, Chinese Academy of Sciences).
There are three forms of life on Earth: bacteria, archaea, and eukaryotes, and each form of life has a different structure of the gene transcription machinery. The successful elucidation of the chloroplast PEP structure fills the last gap in this puzzle. Researcher Zhang Yu said.
"Transcription" is a unique way of reading the "Book of Life". The genetic information of life is written on DNA, which must first be transcribed into RNA before it can be translated into proteins, and finally realize the various functions of life.
Chloroplasts are the site of photosynthesis in plants. About 1.5 billion years ago, primitive eukaryotic cells devoured cyanobacteria, evolved eukaryotic unicellular algae, and finally evolved into higher plants. Chloroplast PEP acts as the "transcription machine" of chloroplast DNA, which is responsible for the development and function of chloroplasts. The long evolutionary process has made the structure of chloroplast PEP very complex and has been unknown to people.
The two research teams of Zhang Yu and Zhou Fei worked closely together to construct chloroplast transgenic tobacco using chloroplast transformation technology. Subsequently, complete chloroplast PEP research samples were obtained by affinity purification. Finally, single-particle cryo-electron microscopy was used to successfully analyze the structure of chloroplast PEP.
Studies have shown that chloroplast PEP has a total of 20 "assembly parts" (protein subunits), which constitute 5 functional modules (catalytic module, scaffold module, protection module, RNA module and regulatory module). The catalytic module is encoded by the chloroplast genome, and its protein subunit originates from cyanobacteria. Other modules are encoded by the nuclear genome, and most of their protein subunits originate in eukaryotic cells and are transported to chloroplasts for assembly after cytoplasmic translation.
On February 28, researcher Zhang Yu introduced the latest research results of chloroplast gene "transcription machine". Photo by Xinhua News Agency reporter Zhang Jiansong.
Chloroplast PEP is the most complex gene transcription machine known at present, and different functional modules cooperate closely with each other to complete the transcription of genetic information from DNA to RNA. The mysteries of life are so wonderful that we are filled with wonder during our research. Zhang Yu said.
International peers believe that this latest study not only lays a foundation for further exploring the working mode of chloroplast gene "transcription machine", understanding the regulatory mode of chloroplast gene expression, and modifying the regulatory network of chloroplast gene expression. It also has broad application prospects in synthetic biology applications, which provides a starting point for improving the efficiency of plant chloroplast bioreactors. At the same time, it also provides a new idea for the improvement of gene expression level in the photosynthesis system, which is expected to help plants efficiently sink carbon.
*:Xinhua.