This group focuses on the molecular mechanisms of plant development, by using the model plant Arabidopsis thaliana. The molecular genetic approaches used include mutant screening and characterizations, molecular cloning of important regulatory genes, and analysis of the gene structures and functions.

Principal Investigator: Dr. Hai Huang, Professor. Email: hh53@sippe.ac.cn
Staff: Dr. Xiao-Feng Cui, Research Associate; Dr. Lin Xu, Research Associate; Min-Huan Zeng; Research Assistant; Hua Wang, Technician
Graduate Students: Zhen-Huan Yuan; Yao Yao; Qi-Li Liu; Xiao-Zhen Yao; Wei Wang; Yang Li; Xiao-Lu Gu; De-Yang Xu; Guang Li; Xiao-Fan Chen; De-Xian Luo; Shu-Jing Liu
Graduated Student: Li-Min Pi, 2002 (PhD); Qi-Hua Ling, 2003 (PhD)

Ribosomal Proteins Promote Leaf Adaxial Identity in Arabidopsis
Establishing abaxial-adaxial polarity is central to leaf morphogenesis and function. Groups of genes that encode different components for leaf patterning have been identified in recent years. These include transcriptional factors, small RNAs, 26S proteasome, and components required for posttranscriptional gene silencing and chromatin remodeling, showing a complex regulatory network and indicating that the regulation occurs at different levels. In this work we report the identification and characterization of asymmetric leaves1/2 enhancer5 and 6 mutants (ae5 and ae6). These two mutants had a phenotype of abnormal leaf patterning, with the abaxial mesophyll features appearing in the adaxial mesophyll domain, and double mutants ae5 as1/2 and ae6 as1/2 produced severely abaxialized leaves. AE5 and AE6 encode the ribosomal large subunit proteins RPL28A and RPL5A, respectively, and mutations in other two ribosomal protein genes, RPL5B and RPL24B, resulted in plant phenotypes similar to those of ae5 and ae6. Because these four ribosomal proteins are located in distinct sites in the ribosomal large subunit, we propose that the conserved translational function of the ribosome may be required for regulating key components during leaf patterning. Collectively, our data indicate that specific ribosome subunit-mediated translational control is essential in leaf polarity establishment.

Major Publications:

1. Ling Q, Yao Y and Huang H. (2008) A model for the 26S proteasome and ribosome actions in leaf polarity formation. Plant Signaling & Behavior 3: 804-805.

2. Zhu Y, Li Z, Xu B, Li H, Wang L, Dong A and Huang H. (2008) Subcellular localizations of the AS1 and AS2 proteins in tobacco BY2 cells and Arabidopsis plants. J. Int. Plant Biol. 50: 897-905.

3. Yao Y, Ling Q, Wang H and Huang H. (2008) Ribosomal proteins promote leaf adaxial identity. Development 135: 1325-1334.

4. Xu B, Li Z, Zhu Y, Wang H, Ma H, Dong A, and Huang H. (2008) Arabidopsis genes AS1, AS2, and JAG negatively regulate boundary-specifying genes to promote sepal and petal development. Plant Physiol. 146: 566-575.

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