(Hypo)Nasty Plant Mutation

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Science  26 Jan 2001:
Vol. 291, Issue 5504, pp. 557
DOI: 10.1126/science.291.5504.557b

A mutation in Arabidopsis may help define a role for double-stranded RNA binding proteins in mediating signals from multiple plant hormones. Lack of function of the HYPONASTIC (meaning movement bending the leaves inward and upward) LEAVES protein (HYL1) leads to a pleiotropic phenotype including decreased response to gravistimulation and reduced apical dominance that appears to reflect altered response to internal and external stimuli. Indeed, Lu and Federoff show that in hyl1 mutants response to the hormones auxin and cytokinin is blunted, whereas plants are hypersensitive to abscisic acid. The HYL1 gene was cloned and encodes a protein with two double-stranded RNA-binding motifs similar to those in human interferon-induced RNA-dependent protein kinase p68. The protein contains a nuclear localization sequence and is concentrated in nuclei. Although how HYL1 contributes to hormonal signaling is not yet clear, the authors propose several possibilities including function as a transcriptional coactivator or corepressor, or control of transcript stability. — LBR

Plant Cell12, 2351 (2000).

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