H. Nakagawa et al., THE SEED-SPECIFIC TRANSCRIPTION FACTOR VP1 (OSVP1) IS EXPRESSED IN RICE SUSPENSION-CULTURED CELLS, Plant and Cell Physiology, 37(3), 1996, pp. 355-362
A seed-specific transcriptional regulator, VPI, is required for the in
duction of ABA-regulated genes that include Lea (late embryogenesis ab
undant protein) genes. Although the induction of one rice Lea gene, Os
em, by ABA is normally restricted to seed tissues, we found that the e
xpression was strongly induced by ABA in the Oc line of rice suspensio
n-cultured cells. Since this observation suggested that rice VP1 (OSVP
1) protein or a functionally similar protein might be expressed in the
cultured cells, we analyzed the expression of Osvp1 in these cells at
both the mRNA and the protein level, we detected Osvp1 mRNA and OSVP1
protein in the cultured cells at levels similar to or higher than tho
se in developing embryos. In the cultured cells, neither the level of
total cellular OSVP1 nor that of nuclear OSVP1 protein was affected by
ABA. Based on the results, the mechanism for the transcriptional regu
lation of VP1-dependent ABA-inducible genes is discussed.