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Identification of three kinds of mutually related composite elements conferring S phase‐specific transcriptional activation
Author(s) -
Taoka Kenichiro,
Kaya Hidetaka,
Nakayama Takuya,
Araki Takashi,
Meshi Tetsuo,
Iwabuchi Masaki
Publication year - 1999
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.1999.00486.x
Subject(s) - biology , gene , promoter , heterologous , transgene , histone , gene expression , genetics , regulatory sequence , microbiology and biotechnology
Summary Conservation of the Oct motif (CGCGGATC) is a remarkable feature of plant histone gene promoters. Many of the Oct motifs are paired with a distinct motif, Hex, TCA or CCAAT‐box, constituting the type I element (CCACGTCANCGATCCGCG), type II element (TCACGCGGATC) and type III element (GATCCGCG‐N14‐ACCAATCA). To clarify the roles of these Oct‐containing composite elements (OCEs) in cell cycle‐dependent and tissue‐specific expression, we performed gain‐of‐function experiments with transgenic tobacco cell lines and plants harboring a derivative of the 35S core promoter/β‐glucuronidase fusion gene in which three or four copies of an OCE had been placed upstream. Although their activities were slightly different, results showed that each of the three types of OCEs could confer the ability to direct S phase‐specific expression on a heterologous promoter. In transgenic plants, the type I and III elements exhibited a similar activity, directing expression in meristematic tissues, whereas the activity of the type II element appeared to be restricted to young cotyledons and maturating guard cells. Mutational analyses demonstrated that the co‐operation of Oct with another module (Hex, TCA or CCAAT‐box) was absolutely required for both temporal and spatial regulation. Thus, OCEs play a pivotal role in regulation of the expression of plant histone genes.