Hen-ming Wu

Research Associate Professor of Biochemistry and Molecular Biology, University of Massachusetts

Email: hmwu@biochem.umass.edu

Ph.D.: Yale University
Postdoctoral Training: Harvard University

Molecular Biology of Plant Development

We are interested in understanding how regulatory circuits interact to control floral development. The four major floral parts—sepals, petals, stamens (the male organs), and carpels (the female organs)—arise sequentially at the floral meristem. They occupy successive whorls from the outside to the inside, respectively, of a flower. Several major regulatory genes have been identified and their roles in floral development extensively studied by several laboratories. Our current effort is centered on understanding how the regulatory gene SUPERMAN from Arabidopsis controls the development of stamens and carpels. SUPERMAN is essential for carpel development as well as for defining the spatial domain for stamen development. In wild type Arabidopsis, SUPERMAN mRNA accumulates in the region of the stamen primordia adjacent to the emerging carpel primordia. Mutant plants defective in the SUPERMAN gene either lack or produce defective carpels, and produce excess number of stamens which occupy their normal position in a flower as well as invade the position which should be occupied by the carpels. These together suggest that SUPERMAN-expressing stamen cells send signals to trigger carpel differentiation in the central domain of the floral meristem as well as to delimit the expression of stamen differentiation program in the central domain. The mechanism underlying the function of SUPERMAN is being investigated using a combination of molecular, biochemical, cell culture, and transgenic approaches.

Representative publications:

Nibau, C., Wu, H-M., Cheung, A. (2006) RAC/ROP GTPases: 'hubs' for signal integration and diversification in plants. Trends Plant Sci. June, [Epub ahead of print].

Li-zhen Tao, Alice Y. Cheung, Candida Nibau, and Hen-ming Wu . (2005). RAC GTPases in Tobacco and Arabidopsis Mediate Auxin-Induced Formation of Proteolytically Active Nuclear Protein Bodies That Contain AUX/IAA Proteins. Plant Cell 17: 2369-2383.

Barend H.J. de Graaf, Alice Y. Cheung, Tatyana Andreyeva, Kathryn Levasseur, Marcia Kieliszewski, and Hen-ming Wu (2005). Rab11 GTPase-Regulated Membrane Trafficking Is Crucial for Tip-Focused Pollen Tube Growth in Tobacco. Plant Cell 17: 2564-2579.

Cheung, A.Y., and Wu, H-M. (2004). Over-expression of an Arabidopsis Formin Stimulates Supernumerary Actin Cable Formation from Pollen Tube Cell Membrane. Plant Cell 16: 257-269.

Chen, C. Y-h., Cheung, A.Y. and Wu, H-M. (2003). Actin depolymerizing factor mediates Rac/Rop GTPase regulated pollen tube growth. Plant Cell 15: 237-249.

Cheung, A.Y., Chen, C., Tao,L-z., Andreyeva, T., Twell, D. and Wu, H-M. (2003). Regulation of pollen tube growth by Rac-like GTPases. J. Exp. Bot. 54: 73-81.

Tao, L-z., Cheung, A.Y., and Wu, H-M. (2002) Plant Rac-like GTPases are activated by auxin and mediate auxin responsive gene expression. Plant Cell 9: 2745-2760.

Chen, C., Wong, E., Vidali, L., Estavillo, A., Hepler, P.K., Wu, H-M., and Cheung, A.Y. (2002) The regulation of actin organization by actin depolymerizing factor (ADF) in elongating pollen tubes. Plant Cell 9: 2175-2190.

Cheung, A.Y., Chen, C., Glaven, R., Vidali, L., Hepler, P.K., and Wu, H-M. (2002) Rab2 regulate vesicular transport between endoplasmic reticulum and Golgi bodies and is important for pollen tube elongation. Plant Cell, 14: 945-962..

Chen, C., Wong, E., Vidali, L., Estavillo, A., Hepler, P.K., Wu, H-M., and Cheung, A.Y. (2002) The regulation of actin organization by actin depolymerizing factor (ADF) in elongating pollen tubes. Plant Cell, in press.

Wu, H.M., de Graaf, B., Mariani, C. and Cheung, A.Y. (2001) Structure and functions of hydroxyproline-rich glycoproteins in plant sexual reproductive tissues. CMLS, 58: 1418-1429.

Cheung, A.Y. and Wu, H-M. 2001. Pollen tube guidance-right on target. Science 293: 1441-1442.

Cheung, A.Y. and Wu, H.M. (2000) Programmed cell death in plant reproductive development. Plant Mol. Biol. 44:267-281.

Wu, H.M. and Cheung, A.Y. (1998) Sexual Reproduction: sex differentiation, pollination and fertilization. Annual Plant Reviews (Sheffield Academic Press) Vol. 1. 181-222.

Cheung, A.Y., Wang, H. and Wu, H-M. (1995) A floral transmitting tissue-specific glycoprotein attracts pollen tubes and stimulates their growth. Cell 82: 383-393.

Wu, H-M. and Cheung, A.Y. (1995) A pollen tube growth stimulatory glycoprotein is deglycosylated by pollen tubes and displays a glycosylation gradient in the flower. Cell 82: 395-403.