The contribution of these authors should be considered equal.
microRNA-directed cleavage of ATHB15 mRNA regulates vascular development in Arabidopsis inflorescence stems
Article first published online: 17 MAR 2005
The Plant Journal
Volume 42, Issue 1, pages 84–94, April 2005
How to Cite
Kim, J., Jung, J.-H., Reyes, J. L., Kim, Y.-S., Kim, S.-Y., Chung, K.-S., Kim, J. A., Lee, M., Lee, Y., Narry Kim, V., Chua, N.-H. and Park, C.-M. (2005), microRNA-directed cleavage of ATHB15 mRNA regulates vascular development in Arabidopsis inflorescence stems. The Plant Journal, 42: 84–94. doi: 10.1111/j.1365-313X.2005.02354.x
- Issue published online: 17 MAR 2005
- Article first published online: 17 MAR 2005
- Received 6 October 2004; revised 10 December 2004; accepted 23 December 2004.
- mRNA cleavage;
- vascular development
Class III homeodomain-leucine zipper proteins regulate critical aspects of plant development, including lateral organ polarity, apical and lateral meristem formation, and vascular development. ATHB15, a member of this transcription factor family, is exclusively expressed in vascular tissues. Recently, a microRNA (miRNA) binding sequence has been identified in ATHB15 mRNA, suggesting that a molecular mechanism governed by miRNA binding may direct vascular development through ATHB15. Here, we show that miR166-mediated ATHB15 mRNA cleavage is a principal mechanism for the regulation of vascular development. In a gain-of-function MIR166a mutant, the decreased transcript level of ATHB15 was accompanied by an altered vascular system with expanded xylem tissue and interfascicular region, indicative of accelerated vascular cell differentiation from cambial/procambial cells. A similar phenotype was observed in Arabidopsis plants with reduced ATHB15 expression but reversed in transgenic plants overexpressing an miR166-resistant ATHB15. ATHB15 mRNA cleavage occurred in standard wheat germ extracts and in Arabidopsis and was mediated by miR166 in Nicotiana benthamiana cells. miR166-assisted ATHB15 repression is likely to be a conserved mechanism that regulates vascular development in all vascular plants.