Circadian oscillation and development-dependent expression of Glycine Rich RNA Binding Proteins in tomato fruits

MULLER, G.; TRIASSI, A; CLARISA ALVAREZ; FALCONE, M.; ANDREO, CARLOS S; LARA, MV; MARIA FABIANA DRINCOVICH

FUNCTIONAL PLANT BIOLOGY

CSIRO PUBLISHING

Lugar: Collingwood; Año: 2014 vol. 41 p. 411 - 423

1445-4408

Glycine-rich RNA-binding proteins (GRPs) are involved in the modulation of the posttranscriptional processing of transcripts and participate as an output signal of the circadian clock. However, neither GRPs nor the circadian rhythmic have been studied in detail in fleshy fruits yet. In the present work, grp1 GRP1 gene family was analyzed in Micro-Tom tomato fruit. Three highly homologous Legrp1 LeGRP1 genes (Legrp1aLeGRP1a-c) were identified. For each gene, three transcriptional products were found, corresponding to the un-spliced pre-RNA, the mature mRNA and the alternatively spliced mRNA (preLegrp1a-c, mLegrp1a-c and asLegrp1a-c, respectively). LeGRPs show the classical RNA recognition motif and glycine-rich region; and were found in the nucleus and in the cytosol of tomato fruit. By using different Escherichia coli mutants, it was found that LeGRP1s harbored in vivo RNA-melting abilities and were able to complement the cold-sensitive phenotype of BX04 cells. Particular circadian profiles of expression, dependent on the fruit developmental stage, were found for each transcriptional Legrp1 form. During ripening off the vine of fruits harvested at the mature green stage, the levels of all transcriptional forms of Legrp1a-c forms drastically increased; however, incubation at 4ºC prevented such increases. Analysis of the expression of all Legrp1a-c forms suggests a positive regulation of expression in tomato fruit. Overall, the results obtained in this work reveal a complex pattern of expression of GRPs in tomato fruit, suggesting they might be involved in posttranscriptional modulation of circadian processes of this fleshy fruit