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The Arabidopsis flowering-time gene LUMINIDEPENDENS is expressed primarily in regions of cell proliferation and encodes a nuclear protein that regulates LEAFY expression

Authors

  • Milo J.. Aukerman,

    1. Department of Biochemistry, University of Wisconsin, 433 Babcock Drive, Madison, WI 53706–1544, USA
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    • Both authors contributed equally to this work.

  • Ilha Lee,

    1. Department of Biology and Research Center for Cell Differentiation, Seoul National University, Seoul 151–742, Korea, and
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    • Both authors contributed equally to this work.

  • Detlef Weigel,

    1. Plant Biology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
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  • Richard M.. Amasino

    1. Department of Biochemistry, University of Wisconsin, 433 Babcock Drive, Madison, WI 53706–1544, USA
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*For correspondence (fax +1 608 262 3453;
e-mail amasino@biochem.wisc.edu).

Summary

Mutations in the LUMINIDEPENDENS ( LD) gene of Arabidopsis thaliana (L.) Heynh. (Arabidopsis) confer a late-flowering phenotype, indicating that LD normally functions to promote the floral transition. RNA and protein blot analyses, along with the analysis of transgenic plants containing a fusion between a genomic fragment of LD and the reporter gene uidA ( GUS), indicate that LD is expressed primarily in apical proliferative regions of the shoot and root, including the shoot apical meristem and leaf primordia. Subcellular localization studies indicate that LD is a nuclear protein, consistent with its previously proposed transcriptional regulatory role. We have also found that in an apetala1 cauliflower ( ap1 cal) background the ld mutation converts the reproductive shoot apex to a more vegetative state, a phenotype that is similar to that seen for the leafy ( lfy) mutant. Furthermore, in situ hybridization analysis indicates that LFY levels are drastically reduced at the apex of ld ap1 cal plants after bolting. These data are consistent with the idea that at least one function of LD is to participate in the regulation of LFY.

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