Whitney E. Hable

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During the establishment of polarity, fucoid algal zygotes adhere to the substratum and select a growth axis according to environmental cues. Since little is known about the early events leading to axis selection, we investigated the chronology of cell adhesion, adhesive deposition, and axis selection induced by light (photopolarization). The requirements(More)
 Previous work has demonstrated that actin plays important roles in axis establishment and polar growth in fucoid zygotes. Distinct actin arrays are associated with fertilization, polarization, growth, and division, and agents that depolymerize actin filaments (cytochalasins, latrunculin B) perturb these stages of the first cell cycle. Rearrangements of(More)
Previous work has demonstrated that dynamic actin arrays are important for axis establishment and polar growth in the fucoid zygote, Silvetia compressa. Transitions between these arrays are mediated by depolymerization of an existing array and polymerization of a new array. To begin to understand how polymerization of new arrays might be regulated, we(More)
There are two quite different modes of polar cell expansion in plant cells, namely, diffuse growth and tip growth. The direction of diffuse growth is determined by the orientation of cellulose microfibrils in the cell wall, which in turn are aligned by microtubules in the cell cortex. The orientation of the cortical microtubule array changes in response to(More)
The role of synthesis in the regulation of abscisic acid accumulation was investigated in the developing maize seed. To do this, expression and regulation of the abscisic acid biosynthetic enzyme phytoene desaturase were examined. Comparison of the gene sequence encoding phytoene desaturase and its transcript in the wild-type and viviparous-5 mutant showed(More)
Plants have evolved novel microtubule (MT) arrays to regulate cell division and cell expansion. How these MT arrangements are managed has been a question of long-standing interest to plant cell biologists. Do plants have unique ways of regulating MTs or have they co-opted mechanisms that are familiar to us from studies in animal and fungal cells? This(More)
Proper cell morphogenesis is dependent on the establishment and expression of cellular polarity. In the fucoid zygote, cell shape is critical for establishing the developmental pattern of the adult, and is achieved by guiding insertion of new membrane and wall to the rhizoid tip. Selection and growth of the appropriate tip site are accompanied by formation(More)
Fucoid zygotes are excellent experimental organisms for investigating mechanisms that establish cell polarity and determine the site of tip growth. A common feature of polarity establishment is targeting endocytosis and exocytosis (secretion) to localized cortical domains. We have investigated the spatiotemporal development of endomembrane asymmetry in(More)