Ribosomal Heterogeneity of Maize Tissues: Insights of Biological Relevance
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In recent years, the selective role of ribosomes in the translational process of eukaryotes has been suggested. Evidence indicates that ribosomal heterogeneity at the level of protein stoichiometry and phosphorylation status differs among organisms, suggesting ribosomal specialization according to the state of development and the surrounding environment. During germination, protein synthesis is an active process that begins with the translation of the mRNAs stored in quiescent seeds and continues with the newly synthesized mRNAs. In this study, we identified differences in the abundance of ribosomal proteins (RPs) in maize embryos at different developmental stages. The relative quantification of RPs during germination revealed changes in six small subunit proteins, S3 (uS3), S5 (uS7), S7 (eS7), two isoforms of S17 (eS17), and S18 (uS13), and nine large subunit proteins, L1 (uL1), L5 (uL18), two isoforms of P0 (uL10), L11 (uL5), L14 (eL14), L15 (eL15), L19 (eL19), and L27 (eL27). Further analysis of ribosomal protein phosphorylation during germination revealed that the phosphorylation of PRP0 (uL10) and P1 increased and that of PRS3 (uS3) decreased in germinated versus quiescent embryos. The addition of insulin during germination increased the phosphorylation of the P1 protein, suggesting that its phosphorylation is controlled by the TOR pathway. Our results indicate that a heterogeneous ribosomal population provides to maize ribosomes during germination a different ability to translate mRNAs, suggesting another level of regulation by the ribosomes.
KeywordsRibosomes Ribosomal protein heterogeneity Ribosomal protein phosphorylation
We thank Dr. Verónica Garrocho-Villegas for her comments to improve the manuscript; also, we wish to thank Biol. Jorge Herrera and Q. Margarita Guzmán from Unidad de Servicio de Apoyo a la Investigación y a la Industria for their support in mass spectrometry analysis and protein identification.
This research was supported by Dirección General de Asuntos del Personal Académico, Universidad Nacional Autónoma de México (DGAPA-UNAM), project PAPIIT IN214214.
- Ban N, Beckmann R, Cate JH, Dinman JD, Dragon F, Ellis SR, Lafontaine DL, Lindahl L, Liljas A, Lipton JM, McAlear MA, Moore PB, Noller HF, Ortega J, Panse VG, Ramakrishnan V, Spahn CM, Steitz TA, Tchorzewski M, Tollervey D, Warren AJ, Williamson JR, Wilson D, Yonath A, Yusupov M (2014) A new system for naming ribosomal protein. Curr Opin Struct Biol 24:165–169CrossRefPubMedPubMedCentralGoogle Scholar
- Barret AJ, Waterworth WM, West CE (2015) Roles of DNA repair pathways in maintenance of seed viability and vigour. Asp Appl Biol 124:15–19Google Scholar
- Dobrenel T, Mancera-Martínez E, Forzani C, Azzopardi M, Davanture M, Moreau M, Schepetilnikov M, Chicher J, Langella O, Zivy M, Robaglia C, Ryabova LA, Hanson J, Meyer C (2016) The Arabidopsis TOR kinase specifically regulates the expression of nuclear genes coding for plastidic ribosomal proteins and the phosphorylation of the cytosolic ribosomal protein S6. Front Plant Sci 7:1611CrossRefPubMedPubMedCentralGoogle Scholar
- Hummel M, Dobrenel T, Cordewener JJ, Davanture M, Meyer C, Smeekens SJ, Bailey-Serres J, America TA, Hanson J (2015) Proteomic LC-MS analysis of Arabidopsis cytosolic ribosomes: identification of ribosomal protein paralogs and re-annotation of the ribosomal protein genes. J Proteome 128:436–449CrossRefGoogle Scholar
- Jiménez-López S, Mancera-Martínez E, Donayre-Torres A, Rangel C, Uribe L, March S, Jiménez-Sánchez G, Sánchez de Jiménez E (2011) Expression profile of maize embryonic axes during germination: translational regulation of ribosomal protein mRNAs. Plant Cell Physiol 52:1719–1733CrossRefPubMedGoogle Scholar