Wu, Hen-ming

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Research Associate Professor, Department of Biochemistry and Molecular Biology
Last Name
Wu
First Name
Hen-ming
Discipline
Biochemistry
Molecular Biology
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Signal transduction pathways in the regulation of plant hormone responses and reproduction
Introduction
The two current major research areas in our laboratory share the common focus of dissecting the signal transduction pathways that mediate plant cell responses to external growth and developmental stimuli.
One area of our work is understanding the signaling of directional pollen tube growth in plant sexual reproduction. Pollen tubes grow in a polar fashion to transport the sperm cells over long distances within the female tissues. The pollen tube growth process is driven by the pollen cytoplasm but is modulated by signals that originate from the female tissues to nourish and guide them to the egg cell. Our efforts are to identify female signal molecules, their receptors on the pollen surface, and signaling molecules that regulate the pollen cellular machinery for growth.
Among the molecules we are working with are female proteins that stimulate and attract pollen tube growth, pollen surface receptor kinases, pollen cell membrane associated Rac-like G-proteins, their downstream effectors in the form of kinases, the actin regulatory protein cofilin and the actin cytoskeleton (the underlying cellular system that drives the pollen tube growth process), and another family of G-proteins known as Rabs that regulate vesicular transport activities, which is essential for pollen tube elongation. Our ultimate goal is to connect these molecules in a signaling pathway that links the female stimuli to the pollen cellular response.
The second area of our work is understanding the signaling of plant growth regulators. Our current focus is on the signaling of auxin-mediated gene expression. Despite its importance and extensive understanding on auxin actions, little is known about how this hormone is perceived at the cell surface and transduced to the cytosol to initiate downstream signaling pathways. Our efforts thus far led to the identification of cell surface associated Rac-like G-proteins as mediators of the auxin signal to auxin-responsive genes. Our ultimate goal is to dissect the cross talks and divergence among various signaling pathways that together produce at least a subset of the highly diversed auxin response.
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Now showing 1 - 3 of 3
  • PublicationOpen Access
    Genetic Modification of Plants
    (2014-01-01) Cheung, Alice; Wu, Hen-Ming
  • PublicationOpen Access
    Pollen Biology
    (2013-01-01) Cheung, Alice; Wu, Hen-Ming
  • PublicationOpen Access
    Hyper, a Hydrogen Peroxide Sensor, Indicates the Sensitivity of the Arabidopsis Root Elongation Zone to Aluminum Treatment
    (2015-01-01) Hernández-Barrera, Alejandra; Velarde-Buendía, Ana; Zepeda, Isaac; Sanchez, Federico; Quinto, Carmen; Sánchez-Lopez, Rosana; Cheung, Alice Y.; Wu, Hen-Ming; Cardenas, Luis
    Emerging evidence indicates that some reactive oxygen species (ROS), such as the superoxide anion radical and hydrogen peroxide (H2O2), are central regulators of plant responses to biotic and abiotic stresses. Thus, the cellular levels of ROS are thought to be tightly regulated by an efficient and elaborate pro- and antioxidant system that modulates the production and scavenging of ROS. Until recently, studies of ROS in plant cells have been limited to biochemical assays and the use of fluorescent probes; however, the irreversible oxidation of these fluorescent probes makes it impossible to visualize dynamic changes in ROS levels. In this work, we describe the use of Hyper, a recently developed live cell probe for H2O2 measurements in living cells, to monitor oxidative stress in Arabidopsis roots subjected to aluminum treatment. Hyper consists of a circularly permuted YFP (cpYFP) inserted into the regulatory domain of the Escherichia coli hydrogen peroxide-binding protein (OxyR), and is a H2O2-specific ratiometric, and therefore quantitative, probe that can be expressed in plant and animal cells. Now we demonstrate that H2O2 levels drop sharply in the elongation zone of roots treated with aluminum. This response could contribute to root growth arrest and provides evidence that H2O2 is involved in early Al sensing.