(03414)Structural Analysis and Identification of Cis-Elements of Rice osRACD Gene

Yun-Zhe XU1,2, Rui-Lin
YOU2, and Nai-Hu WU*
(¹Institute of Genetics and Developmental Biology, Chinese Academy of Sciences,
Beijing 100080, China;
2College of Life Sciences, Peking University, Beijing 100871, China)

Abstract The osRACD gene
correlated with fertility transformation in the photoperiod sensitive genic
male sterile rice (PGMR), Nongken 58S, encoded a rice (Oryza sativa L.
ssp. japonica) small GTPase belonging to the Rac/Rho family. Inverse
PCR was performed to amplify a fragment about 1.4 kb in 5′ upstream region of
the osRACD promoter. Deletion mutation and gel mobility shift assay characterized
two fragments (-799 to -686 nt, and -686 to -431 nt) in the osRACD promoter
that could be involved in its transcriptional regulation. When these two deletion
fragments were used as probe respectively, a retarded band appeared in the nuclear
extracts of fertile 58S rice under short day (58S-SD). Whereas no retarded band
was shown in the nuclear extracts of sterile 58S rice under long day (58S-LD).
Competition assay indicated that the factors in the retarded bands binding to
these two fragments were the same trans-acting factor (termed rice factor,
RF). The binding affinity of RF was affected by phosphorylation and was higher
in SD-growth rice than that of LD-growth rice.

Key words photoperiod-sensitive
male genic sterile rice; osRACD gene; photoperiod fertility transformation;
cis-element

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Received: October 23, 2003 Accepted:
January 15, 2004
This work was supported by the grants from the Transgenic Plant Research Project
of Ministry of Science and Technology (J00-A005), the Major State Basic Research
Development Program of China (2001CB1088) and the National High Technology Research
and Development Program of China (20002A224061)
*Corresponding author: Tel, 86-10-82610114; E-mail, [email protected]