title: Light- and cytokinin-induced changes in the levels of leucine and tyrosine isoaccepting tRNA species and modified nucleotide contents of total tRNA in cucumber seedlings.
abstract: We have determined relative levels of chloroplast leucine and tyrosine isoaccepting tRNAs and modified nucleotide contents from total tRNAs isolated from dark-grown, light-grown, N6-isopentenyladenine (i6A)-treated dark-grown and i6A-treated light-grown cucumber seedlings. Significant increases in the relative amounts of tRNA(Leu)2 and tRNA(Leu)3 were observed in the i6A-treated dark-grown seedlings compared to dark-grown, light-grown and i6A-treated light-grown seedlings. On the other hand, i6A-treated light-grown seedlings tRNA(Tyr)1 increased to 85% of total tRNAs(Tyr) from about 9% in light-grown seedlings and tRNA(Tyr)2 decreased to 15% compared with 91% in light-grown seedlings. Analysis of modified nucleotide of total tRNAs indicated that pT, pI, pm1A, pm5C, pGm, pm1G, pm2G and pm7G contents were significantly higher in the total tRNA of i6A-treated dark-grown seedlings than those from untreated dark-grown seedlings. Illumination of 8-day-old dark-grown seedlings for 12 h increased the contents of pT, pI, pGm and pm1G when compared to 8-day-old dark-grown seedlings with extended growth for 12 h in dark. On the contrary, i6A had no stimulatory effect in the contents of modified nucleotide in the light-grown seedlings.
authors: Department of Biochemistry, Indian Institute of Science, Bangalore, India.
authors: M V
authors: MV
authors: Sreenagesh
authors: C
authors: C
authors: Jayabaskaran
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D002736:Chloroplasts / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D002845:Chromatography; D018553:Cucumis sativus / Q000187:drug effects / Q000378:metabolism*; D003583:Cytokinins / Q000494:pharmacology*; D003624:Darkness; D007541:Isopentenyladenosine; D008027:Light; D009711:Nucleotides / Q000378:metabolism*; D018749:RNA, Plant / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism*; D012356:RNA, Transfer, Leu / Q000378:metabolism*; D012365:RNA, Transfer, Tyr / Q000378:metabolism*
chemical_list: D003583:Cytokinins; D009711:Nucleotides; D018749:RNA, Plant; D012356:RNA, Transfer, Leu; D012365:RNA, Transfer, Tyr; C001478:N(6)-(delta(2)-isopentenyl)adenine; D007541:Isopentenyladenosine; D012343:RNA, Transfer; D000225:Adenine