Sequential thin-section, tracer (K-pyroantimonate, lanthanum, ruthenium red, and horseradish peroxidase), and freeze-fracture studies were conducted on embryos and larvae of Rana pipiens to determine the steps involved in gap junction assembly during neurulation. The zonulae occludentes, which join contiguous neuroepithelial cells, fragment into solitary domains as the neural groove deepens. Th...

Neurulation is the process by which progenitors of the central nervous system are shaped, separated from and brought beneath the epidermis. The cellular basis of these movements have been investigated in amphibians (Jacobson, 1981; Jacobson and Gordon, 1976; Keller et al., 1992b), chicken (Schoenwolf and Smith, 1990b; Smith and Schoenwolf, 1997) and mice (Bush et al., 1990; Sausedo and Schoenwo...

The development of multicellular organisms is dependent on the tight coordination between tissue growth and morphogenesis. The stereotypical orientation of cell divisions has been proposed to be a fundamental mechanism by which proliferating and growing tissues take shape. However, the actual contribution of stereotypical division orientation (SDO) to tissue morphogenesis is unclear. In zebrafi...

Genetic mouse models are an important tool in the study of mammalian neural tube closure (Gray & Ross, 2009; Ross, 2010). However, the study of mouse embryos in utero is limited by our inability to directly pharmacologically manipulate the embryos in isolation from the effects of maternal metabolism on the reagent of interest. Whether using a small molecule, recombinant protein, or siRNA, del...