%0 Journal Article
%T Changes in -Tubulin Protein Distribution in Zebrafish (Danio rerio) Oocytes and the Early Cleavage-Stage Embryo
%A Jianxiong Liu
%A Charles A. Lessman
%J ISRN Developmental Biology
%D 2013
%R 10.1155/2013/920265
%X We investigated the distribution of -tubulin in zebrafish oocytes and embryos using epifluorescent or confocal microscopy and -tubulin antibodies. During meiotic maturation of zebrafish oocytes, -tubulin begins redistribution from oocyte ooplasm and cortex to the future blastodisc region at the animal pole. In activated eggs, -tubulin was uniformly distributed in the enlarging blastodisc with label emanating from the yolk cell. In newly fertilized eggs, -tubulin was evenly distributed in blastomere cytoplasm, with the presence of pronuclei but initially lacking discernable centrosomes. During early cleavage, especially at the eight-cell stage, striking arc-shaped/rings (A/R) of putative centrosomes were detected. Decreasing -tubulin was seen in yolk cells while early cleavage blastomeres had strong cytoplasmic label along with obvious A/R arrays. In addition, we found the orientation of the A/R array and nuclear division alternated by about 90 degrees for each cell cycle along with alternation of punctate and A/R arrays. 1. Introduction The microtubule cytoskeleton is essential for a variety of cellular processes, including cell movement, organelle transport, and cell division. Moreover, in oocytes and early embryos, microtubules have been implicated in localization of important embryonic determinants such as bicoid mRNA in Drosophila [1] and Vg1 mRNA in Xenopus [2] as well as trafficking cell components such as -catenin in cleaving zebrafish embryos [3]. Recently, imaging of cytoskeleton in live zebrafish embryos has been described and the field reviewed [4]. The highly ordered microtubular array found in typical eukaryotic cells is organized by the microtubule-organizing center (MTOC). MTOCs organize microtubules by initiating noncovalent assembly of -/ -tubulin heterodimers, anchoring them at their minus ends, and facilitating microtubule extension at the rapidly growing plus ends [5]. The morphology, subcellular localization, and molecular makeup of MTOCs vary across different species and different cell types within single species. The major MTOC in proliferating animal cells is the centrosome. Because of its central role in many essential aspects of cell physiology, both in interphase and during cell division, intense research activity has been carried out to characterize centrosomes [6¨C8]. Recently a review, describing centrosome and basal body research in zebrafish, has been published that enumerates the advantages of the zebrafish model in the study of MTOCs [9]. In most animal cells, centrosomes are composed of a pair of centrioles, surrounded
%U http://www.hindawi.com/journals/isrn.developmental.biology/2013/920265/