We have analyzed the development of leaf shape and vascular pattern in leaves mutant for ASYMMETRIC LEAVES1 (AS1) or AS2 and compared the timing of developmental landmarks to cellular response to auxin, as measured by expression of the DR5:beta-glucuronidase (GUS) transgene and to cell division, as measured by expression of the cycB1:GUS transgene. We found that the earliest visible defect in b...

Cell polarization and asymmetric cell divisions play important roles during development in many multicellular eukaryotes. Fucoid algae have a long history as models for studying early developmental processes, probably because of the ease with which zygotes can be observed and manipulated in the laboratory. This review discusses cell polarization and asymmetric cell divisions in fucoid algal zyg...

Throughout the development of an organism, it is essential that the cell cycle machinery is fine-tuned to generate cells of different fate. A series of asymmetric cell divisions leads to lineage specification. The Caenorhabditis elegans embryo is an excellent system to study various aspects of the early embryonic cell cycle. The invariant nature of the rapid cell divisions is the key feature fo...

It has long been recognized that alterations in cell shape and polarity play important roles in coordinating lymphocyte functions. In the last decade, a new aspect of lymphocyte polarity has attracted much attention, termed asymmetric cell division (ACD). ACD has previously been shown to dictate or influence many aspects of development in model organisms such as the worm and the fly, and to be ...

The par genes were discovered in genetic screens for regulators of cytoplasmic partitioning in the early embryo of C. elegans, and encode six different proteins required for asymmetric cell division by the worm zygote. Some of the PAR proteins are localized asymmetrically and form physical complexes with one another. Strikingly, the PAR proteins have been found to regulate cell polarization in ...

Asymmetric cell division is a mechanism for achieving cellular diversity. In C. elegans, many asymmetric cell divisions are controlled by the Wnt-MAPK pathway through POP-1/TCF. It is poorly understood, however, how POP-1 determines the specific fates of daughter cells. We found that nob-1/Hox, ceh-20/Pbx, and a Meis-related gene, psa-3, are required for asymmetric division of the T hypodermal ...

The type and number of cell divisions of neuronal progenitors determine the number of neurons generated during the development of the vertebrate central nervous system. Over the past several years, there has been substantial progress in characterizing the various kinds of neuronal progenitors and the types of symmetric and asymmetric divisions they undergo. The understanding of the cell-biologi...

Specification of germline and somatic cell lineages in C. elegans originates in the polarized single-cell zygote. Several cell-fate determinants are partitioned unequally along the anterior-posterior axis of the zygote, ensuring the daughter cells a unique inheritance upon asymmetric cell division. Recent studies have revealed that partitioning of the germline determinant PIE-1 and the somatic ...

Cells exhibit morphological and molecular asymmetries that are broadly categorized as cell polarity. The cell polarity established in early embryos prefigures the macroscopic anatomical asymmetries characteristic of adult animals. For example, eggs and early embryos have polarized distributions of RNAs and proteins that generate global anterior/posterior and dorsal/ventral axes. The molecular p...

Asymmetric division of Drosophila neuroblasts, sensory organ precursor cells, and cells in the procephalic neurogenic region involves the segregation of Numb and Prospero proteins into one of the two daughter cells. We have isolated a novel gene, miranda, based on the ability of its gene product to interact with the Prospero asymmetric localization domain. miranda expression coincides spatially...