Plant Growth Regulation

, Volume 16, Issue 1, pp 73–81 | Cite as

Variations in the levels of aminoacylation and modified nucleotide content between total tRNAs from chloroplasts and etioplasts in cucumber cotyledons

  • Chelliah Jayabaskaran
  • Shailaja Hande


Total tRNAs isolated from chloroplasts and etioplasts of cucumber cotyledons were compared with respect to amino acid acceptance, isoacceptor distribution and extent of modification. Aminoacylation of the tRNAs with nine different amino acids studied indicated that the relative acceptor activities of chloroplast total tRNAs for four amino acids are significantly higher than etioplast total tRNAs. Two dimensional polyacrylamide gel electrophoresis (2D-PAGE) of chloroplast total tRNAs separated at least 32 spots, while approximately 41 spots were resolved from etioplast total trNAs. Comparison of the reversed-phase chromatography (RPC-5) profiles of chloroplast and etioplast leucyl-, lysyl-, phenylalanyl-, and valyl-tRNA species showed no qualitative differences in the elution profiles. However, leucyl-, lysyl- and valyl-tRNA species showed quantitative differences in the relative amounts of the isoaccepting species present in chloroplasts and etioplasts. The analysis of modified nucleotides of total tRNAs from the two plastid types indicated that total tRNA from etioplasts was under-modified with respect to ribothymidine, isopentenyladenosine/hydroxy-isopentenyladenosine, 1-methylguanosine and 2-o-methylguanosine. This indicates that illumination may cause de novo synthesis of chloroplast tRNA-modifying enzymes encoded for by nuclear genes leading to the formation of highly modified tRNAs in chloroplasts. Based on these results, we speculate that the observed decrease in levels of aminoacylation, variations in the relative amounts of certain isoacceptors, and differences in the electrophoretic mobilities of some extra tRNA spots in the etioplast total tRNAs as compared to chloroplast total tRNAs could be due to some partially undermodified etioplast tRNAs. Taken together, the data suggested that the light-induced transformation of etioplasts into chloroplasts is accompanied by increases in the relative levels of some functional chloroplast tRNAs by post transcriptional nucleotide modifications.

Key words

cucumber chloroplast isoaccepting tRNA light regulation modified nucleotide tRNA aminoacylation 



two dimensional polyacrylamide gel electrophoresis


reversed phase chromatography


two dimensional thin layer chromatography

pseudouridine 5′-phosphate


dihydrouridine 5′-phosphate


ribothymidine 5′-phosphate


1-methyladenosine 5′-phosphate


2-methyladenosine 5′-phosphate


N6-isopentenyladenosine 5′-phosphate


N6-hydroxyisopentenyladenosine 5′-phosphate


5-methylcytidine 5′-phosphate


O2-methylcytidine 5′-phosphate


O2-methylguanosine 5′-phosphate


1-methylguanosine 5′-phosphate


2-methylguanosine 5′-phosphate


7-methylguanosine 5′-phosphate


O2-methyluridine 5′-phosphate


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Brenchley JE and Williams LS (1975) Transfer RNA involvement in the regulation of enzyme synthesis. Annu Rev Microbiol 29: 251–274Google Scholar
  2. 2.
    Burkard G, Vaultier JP and Weil JH (1972) Differences in the level of plastid-specific tRNAs in chloroplasts and etioplasts of Phaseolus vulgaris. Phytochemistry 11: 1351–1353Google Scholar
  3. 3.
    Deng X-W and Gruissen W (1987) Control of plastid gene expression during development: the limited role of transcriptional regulation. Cell 49: 379–387Google Scholar
  4. 4.
    Gallagher TF, Jenkins GI and Ellis RJ (1985) Rapid modulation of transcription of nuclear genes encoding chloroplast proteins by light. FEBS Lett 186: 241–245Google Scholar
  5. 5.
    Hegg LA and Thurlow DL (1990) Residual tRNA secondary structure in ‘denaturing’ 8M Urea/TBE polyacrylamide gels: effects on electrophoretic mobility and dependency on prior chemical modification of the tRNA. Nucl Acids Res 18: 2993–3000Google Scholar
  6. 6.
    Jayabaskaran C, Kuntz M, Guillemaut P and Weil JH (1990) Variations in the levels of chloroplast tRNA and aminoacyl-tRNA synthetases in senescing leaves of Phaseolus vulgaris. Plant Physiol 92: 136–140Google Scholar
  7. 7.
    Jayabaskaran C and Puttaraju M (1993) Fractionation and identification of cytoplasmic tRNAs and structural characterization of a phenylalanine and a leucine tRNA from cucumber hypocotyls. Biochem Mol Biol Int 31: 983–995Google Scholar
  8. 8.
    Kedzierski W, Sulewski T and Pawelkiewicz J (1979) Levels of aminoacylation of methionine tRNAs in germinating lupin cotyledons. Plant Sci Lett 14: 373–380Google Scholar
  9. 9.
    Klein RR, Mason HS and Mullet JE (1988) Light-regulated translation of chloroplast proteins. Transcript of psaA-psaB, psbA and rbcL are associated with polysomes in dark-grown and illuminated barley seedlings. J Cell Biol 106: 289–301Google Scholar
  10. 10.
    Krupinska K and Apel K (1989) Light-induced transformation of etioplasts to chloroplasts of barley without transcriptional control of plastid gene expression. Mol Gen Genet 219: 467–473Google Scholar
  11. 11.
    Kuchino Y, Mizushima H and Nishimura S (1990) Nucleotide sequence analysis and identification of modified nucleotides of tRNA. In: Cherayil JD (ed) Transfer RNAs and other soluble RNAs, pp 69–82. Boca Raton: CRC pressGoogle Scholar
  12. 12.
    Kuhlemeier C, Green PJ and Chua N-H (1987) Regulation of gene expression in higher plants. Annu Rev Plant Physiol 38: 221–257Google Scholar
  13. 13.
    Marechal-Drouard L, Weil JH and Dietrich A (1993) Transfer RNAs and transfer RNA genes in plants. Annu Rev Plant Physiol Mol Biol 44: 13–32Google Scholar
  14. 14.
    McClain WH (1993) Rules that govern tRNA identity in protein synthesis. J Mol Biol 234: 257–280Google Scholar
  15. 15.
    Merrick WC and Dure LS (1972) The developmental biochemistry of cotton seed embryogenesis and germination IV Levels of cytoplasmic and chloroplast transfer ribonucleic acid species. J Biol Chem 247: 7988–7999Google Scholar
  16. 16.
    Mettler IJ and Romani RJ (1976) Quantitative changes in tRNA during ethylene-induced ripening (ageing) of tomato fruits. Phytochemistry 15: 25–28Google Scholar
  17. 17.
    Mosinger E, Batschauer A, Schafer E and Apel K (1985) Phytochrome control of in vitro transcription of specific genes in isolated nuclei from barley (Hordeum vulgare). Eur J Biochem 147: 137–142.Google Scholar
  18. 18.
    Mullet JE (1988) Chloroplast development and gene expression. Annu Rev Plant Physiol Plant Mol Biol 39: 475–502Google Scholar
  19. 19.
    Pearson R, Weiss JF and Kelmers AD (1971) Improved separation of tRNAs on polychlorotrifluoroethylene supported reversed-phase chromatography column. Biochim Biophys Acta 228: 770–774Google Scholar
  20. 20.
    Pfitzinger H, Guillemaut P and Weil JH (1987) Adjustment of the tRNA population to the codon usage in chloroplasts. Nucl Acids Res 15: 1377–1386Google Scholar
  21. 21.
    Pfitzinger H, Marechal-Drouard L, Pillay DTN, Weil JH and Guillemaut P (1990) Variations during leaf development of the relative amounts of two bean (Phaseolus vulgaris) chloroplast tRNAsPhe which differ in their minor nucleotide content. Plant Mol Biol 14: 969–975Google Scholar
  22. 22.
    Puttaraju M and Jayabaskaran C (1988) Effect of light on nucleotide modifications in the transfer RNA of cucumber. J Biosci 13: 367–378Google Scholar
  23. 23.
    Racz I, Juhasz A, Kiraly I and Lasaztity D (1981) The changes of minor nucleotide content of tRNAPhe of wheat germs (Triticum aestivum) during greening. Plant Sci Lett 21: 371–374Google Scholar
  24. 24.
    Silberklang M, Gillum AM and RajBhandary UL (1979) Use of in vitro 32P labelling in the sequence analysis of non radioactive tRNAs. Methods Enzymol 59: 58–109Google Scholar
  25. 25.
    Silverthorne J and Tobin E (1984) Demonstration of transcriptional regulation of specific genes by phytochrome action. Proc Natl Acad Sci USA 81: 1112–1116Google Scholar
  26. 26.
    Steinmetz A and Weil JH (1986) Isolation and characterization of chloroplast and cytoplasmic transfer RNAs. Methods Enzymol 118: 212–231Google Scholar
  27. 27.
    Subramanian AR (1993) Molecular genetics of chloroplast ribosomal proteins. Trends Biochem Sci 18: 117–180Google Scholar

Copyright information

© Kluwer Academic Publishers 1995

Authors and Affiliations

  • Chelliah Jayabaskaran
    • 1
  • Shailaja Hande
    • 1
  1. 1.Department of BiochemistryIndian Institute of ScienceBangaloreIndia

Personalised recommendations