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Regulation of the Osem gene by abscisic acid and the transcriptional activator VP1: analysis of cis ‐acting promoter elements required for regulation by abscisic acid and VP1
Author(s) -
Hattori Tsukaho,
Terada Tomoko,
Hamasuna Satoshi
Publication year - 1995
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1995.07060913.x
Subject(s) - abscisic acid , biology , promoter , gene , gene expression , activator (genetics) , microbiology and biotechnology , transcriptional regulation , regulation of gene expression , regulatory sequence , mutant , genetics
Osem , a rice gene homologous to the wheat Em gene, which encodes one of the late‐embryogenesis abundant proteins was isolated. The gene was characterized with respect to control of transcription by abscisic acid (ABA) and the transcriptional activator VP1, which is involved in the ABA‐regulated gene expression during late embryo‐genesis. A fusion gene (Osem‐GUS) consisting of the Osem promoter and the bacterial β‐glucuronidase (GUS) gene was constructed and tested in a transient expression system, using protoplasts derived from a suspension‐cultured line of rice cells, for activation by ABA and by co‐transfection with an expression vector (35S‐Osvp1) for the rice VP1 (OSVP1) cDNA. The expression of Osem‐GUS was strongly (40‐ to 150‐fold) activated by externally applied ABA and by over‐expression of (OS)VP1. The Osem promoter has three ACGTG‐containing sequences, motif A, motif B and motif A′, which resemble the abscisic acid‐responsive element (ABRE) that was previously identified in the wheat Em and the rice Rab16 . There is also a CATGCATG sequence, which is known as the Sph box and is shown to be essential for the regulation by VP1 of the maize anthocyanin regulatory gene C1 . Focusing on these sequence elements, various mutant derivatives of the Osem promoter in the transient expression system were assayed. The analysis revealed that motif A functions not only as an ABRE but also as a sequence element required for the regulation by (OS)VP1.