ABSTRACT
On the page 553 Acknowledgements should be as follows: The study was supported by the Russian Science Foundation (grant 14-25-00024-P).
ABSTRACT
In primary culture of mouse hippocampal neurons, peptide EDR (200 ng/ml) under conditions of amyloid synaptotoxicity (a model of Alzheimer's disease) increased the number of mushroom spines by 71% and returned this parameter to the normal level. Under the same conditions, tripeptide KED (200 ng/ml) increased the number of mushroom spines in hippocampal neurons by 20%. Tripeptide EDR can be recommended for further experimental study as a candidate neuroprotective agent for prevention and treatment of Alzheimer's disease.
Subject(s)
Alzheimer Disease/metabolism , Amyloid beta-Peptides/metabolism , Dendritic Spines/metabolism , Hippocampus/cytology , Neurons/drug effects , Peptides/therapeutic use , Animals , Cells, Cultured , Disease Models, Animal , MiceABSTRACT
The protein environment of mRNA 3' of the A-site codon (the decoding site) in the human 80S ribosome was studied using a set of oligoribonucleotide derivatives bearing a UUU triplet at the 5'-end and a perfluoroarylazide group at one of the nucleotide residues at the 3'-end of this triplet. Analogues of mRNA were phased into the ribosome using binding at the tRNAPhe P-site, which recognizes the UUU codon. Mild UV irradiation of ribosome complexes with tRNAPhe and mRNA analogues resulted in the predominant crosslinking of the analogues with the 40S subunit components, mainly with proteins and, to a lesser extent, with rRNA. Among the 40S subunit ribosomal proteins, the S3 protein was the main target for modification in all cases. In addition, minor crosslinking with the S2 protein was observed. The crosslinking with the S3 and S2 proteins occurred both in triple complexes and in the absence of tRNA. Within triple complexes, crosslinking with S15 protein was also found, its efficiency considerably falling when the modified nucleotide was moved from positions +5 to +12 relative to the first codon nucleotide in the P-site. In some cases, crosslinking with the S30 protein was observed, it was most efficient for the derivative containing a photoreactive group at the +7 adenosine residue. The results indicate that the S3 protein in the human ribosome plays a key role in the formation of the mRNA binding site 3' of the codon in the decoding site.
Subject(s)
Codon/metabolism , RNA, Messenger/metabolism , RNA, Ribosomal/metabolism , Ribosomal Proteins/metabolism , Base Sequence , Binding Sites , Codon/chemistry , Humans , Molecular Sequence Data , Nucleic Acid Conformation , Oligoribonucleotides/chemistry , RNA, Messenger/chemistry , RNA, Ribosomal/chemistry , Ribosomal Proteins/chemistryABSTRACT
Positioning of stop codon and the adjacent triplet downstream of it with respect to the components of human 80S termination complex was studied with the use of mRNA analogues that bore stop signal UPuPuPu (Pu is A or G) and photoactivatable perfluoroaryl azide group. This group was attached to one of nucleotides of the stop signal or 3' of it (in positions +4 to +9 with respect to the first nucleotide of the P site codon). It was shown that upon mild UV irradiation the mRNA analogues crosslinked to components of model complexes imitating state of 80S ribosome in the course of translation termination. It was found that termination factors eRF1 and eRF3 do not affect mutual arrangement of stop signal and the 18S rRNA. Factor eRF1 was shown to cross-link to modified nucleotides in positions +5 to +9 (ability of eRF1 to cross-link to stop codon nucleotide in position +4 was shown earlier). Fragments of eRF1 containing cross-linking sites of the mRNA analogues were determined. In fragment 52-195 (containing the N-domain and a part of the M-domain) we have found cross-linking sites of the analogues that bore modifying groups on A or G in positions +5 to +9 or at the terminal phosphate of nucleotide in position +7. For mRNA analogues bearing modifying groups on G site of cross-linking from positions +5 to +7 was found in the eRF1 fragment
