Molecular mechanism of antizyme frameshifting
Grant-in-Aid for Scientific Research (B)
|Allocation Type||Single-year Grants|
|Research Institution||Jikei University School of Medicine|
MATSUFUJI Senya Jikei University School of Medicine, Faculty of Medicine, Associate Professor, 医学部, 助教授 (50192753)
|Project Period (FY)
1996 – 1998
Completed(Fiscal Year 1998)
|Budget Amount *help
¥6,700,000 (Direct Cost : ¥6,700,000)
Fiscal Year 1998 : ¥1,400,000 (Direct Cost : ¥1,400,000)
Fiscal Year 1997 : ¥1,300,000 (Direct Cost : ¥1,300,000)
Fiscal Year 1996 : ¥4,000,000 (Direct Cost : ¥4,000,000)
|Keywords||translational frameshifting / recoding / translational control / ornithine decarboxylase antizyme / polyamines / expression vector / DNA transfection / Schizosaccharomyces pombe / 発現バクター / 翻訳終結因子 / ゼブラフィッシュ / トランスフェクション|
1. Two sequence elements on antizyme mRNA, a pseudoknot structure downstream to and a GC-rich region upstream to the frameshift site, were confirmed to be stimulatory signals for the frameshifting both in cell-free and animal cell culture systems. The upstream element was shown to interact with elongating ribosomes. These cis-acting elements also increased the efficiencies of other frameshift events such as viral -l frameshifting. However, the frameshiftstimulating effect of polyamines was not mediated by interaction between the cis-acting elements and polyamines. Certain recoding phenomena at the terminator codons such as +1 frameshifting on E.coli release factor 2 (RE2) signal and stop codon readthrough on viral signals were also enhanced by polyamines. The possibility that polyamines repress the termination process was not supported by experimental results. The polyamine-interacting site(s)for frameshift stimulation is to be determined in the future.
2. Analysis of frameshift efficie
ncy and polyamine contents in transfected mammalian cells which stably express the reporter construct revealed that the unbound polyamines are responsible for the stimulation of antizyme frameshifting in the cells.
3. Some compounds which either stimulate or inhibit antizyme frameshifting were found.
Agmatine was one of the stimulatory substances, agmatine and showed anti-proliferative effect through depletion of the cellular polyamines. Diamine derivatives which inhibit the frameshifting in competition with polyamines will be useful as molecular probes to search the polyamine-interacting site(s).
4. Antizyme cDNAs of chicken and zebrafish were isolated. Alternative functions of new antizyme isoforms were also found. These results revealed that antizyme and its frameshifting are phylogenetically old and widely distribute.
5. A fission yeast, Schizosaccharomyces pombe, was shown to be a suitable model organism for genetic screening of trans-acting factors involved in antizyme frameshifting. Construction of an assay system for polyamine-dependent antizyme frameshifting in S.pombe is underway. Less
Research Output (24results)