Blooming time for plant glycine-rich proteins.

Glycine-rich regions are proposed to be involved in protein-protein and protein-nucleic acid interactions in some mammalian protein families. In plants the occurrence of quasi-repetitive glycine-rich peptides has been reported in different species. They are characterized by having the glycine residues arranged in characteristic repetitive structural motifs, but with distinct primary sequence. The expression of genes encoding glycine-rich proteins (GRP) is developmentally regulated, and also induced, in several plant genera, by physical, chemical and biological factors. The diverse expression pattern of GRP genes, taken together with the distinct sub-cellular localisation of some GRP groups indicate that these proteins are involved in several independent physiological processes. Notwithstanding the absence of a clear definition of the role of GRPs in plant cells, experimental data coming from different research groups have shed some light on the biological function of some GRPs. One of these proteins is AtGRP2, a member of the Cold-Shock Domain protein family in Arabidopsis. AtGRP2 is a nucleo-cytoplasmic protein involved in Arabidopsis development. Expression analysis revealed that the AtGRP2 gene is active in meristematic tissues, being modulated during flower development. Downregulation of AtGRP2 gene using gene silecing techniques resulted in early flowering, altered stamen number and affected seed development.