The University of Munich has revealed a series of 90S ribosome precursors assembled.

On August 1, 2019, a series of 90S riglys precursor intermediate structures from the Roland Beckmann Laboratory at the University of Munich (Dr. Cheng Netdong, first author) and their co-authors published an article in Molecular Cell online on Thermophile 90S Pre-ribosomeS StructureS SVic 18S rRNA Subdomain Integration, which revealed the intermediate structure of the 90S ribose precursors. 3'major domain, 3'minor domain) is assembled in reverse order into the Pre-A1 90S ribosome precursor. Based on previous studies, Dr.
Cheng, further identified Kre33/Enp2/Bfr2/Lcp5 and Noc4/Nop14/Emg1/Enp1/Rrp12 as module compounds, combined with 5' and 3' domains in 18S, respectively.
the authors selected two proteins, Kre33 and Noc4, as bait, and used step-by-step purification to isolate samples of 90S ribosome precursors that purified the heat-thirsty furshell bacteria.
obtained six different assembly intermediate 90S ribosome precursor structures, all predate the Pre-A1 90S ribosome precursors, through single-particle cryoscope analysis.
two of the Central sub-domains in state a and b are combined with the Rrp5 factor, resulting in an immature state.
because it is the same structure as purified in hunger conditions, the authors classify it as a 90S-assembled side line.
in the main line, most of the 5' domains in state A have not been stablely combined into 90S, with only Kre33 dipolymers, with the central and 3' domains (major and minor).
as it matures, in state B1, the 5' domain and the remaining Kre33 module factor (Enp2/Bfr2/Lcp5) begin to be steadily combined on the 90S, resulting in a complete Kre33 module.
from states B1 to B2 and C, the UtpC module began to bind steadily to the Central domain, and the ribosome protein eS27 was recruited in state C.
in state C, the h41 and h42 regions of 18S rRNA in the 3' domain have matured to release the assembly factor Utp30 while recruiting the ribosome protein eS19.
it appears that 18S rRNA's 3' domain (major and minor) was first stablely combined into a 90S ribosome precursor, followed by central and 5' domains combined to form a stable Pre-A1 90S ribosome precursor structure. further biochemical experiments
proved that the Kre33 module guided the early integration of the 5' domain.
the study showed that, contrary to the transcription order of 18S rRNA, the order of assembly of the four sub-domains was from 3'to 5', and the same phenomenon occurred during the assembly process of 60S Grand Subaky.
cells use this to check for transcription to be complete, thus ensuring the normal folding of ribosome RNA, thus avoiding assembly abnormalities and disease.
study background eukaleut ribofsome assembly is one of the most important and energy-consuming processes in the cell, and is also the component of nucleokernel kernels in the nucleus, consisting of 4 rRNAs shear and folding, as well as the translation, transport and assembly of 80 ribosome proteins.
, more than 200 assembly factors were involved.
recent years found that the assembly abnormality of ribosomes is closely related to human diseases and has become a hot research target for the treatment of many diseases.
yeast and nucleosomes of phage-hued bacteria begin with RNA polymerase I transcribing of 35S rRNA, which in turn includes 18S rRNA and datum-based 5.8S, 25S rRNA.
35S rRNA transcription, ribosome assembly factors are sequentially bound to rRNA and first assembled into a 40S sub-sub-primitive precursor, a 90S ribosome precursor.
with the cutting of 35S rRNA median point 2 or site 3, the 90S ribosome precursor is released, through a series of assembly factors, from the nucleozone through the nucleogene region and the core pore complex into the cytoplasm, and eventually matured to 40S small sub-subtype.
, the structure of 90S (Pre-A1 90S) of one of the states that has not yet been cut at the A1 bit has been parsed.
but the process of assembling the pre-A1 90S ribosome precursor within the cell is still unknown.
Source: BioArt.