Direct cell lineage analysis in Drosophila melanogaster by time-lapse, three-dimensional optical microscopy of living embryos.

Abstract

Abstract. One of the first signs of cell differentiation in the Drosophila melanogaster embryo occurs 3 h after fertilization, when discrete groups of cells enter their fourteenth mitosis in a spatially and temporally patterned manner creating mitotic domains (Foe, V. E., and G. M. Odell. 1989. Am. Zool. 29:617-652). To determine whether cell residency in a mitotic domain is determined solely by cell position in this early embryo, or whether cell lineage also has a role, we have developed a technique for directly analyzing the behavior of nuclei in living emb~os. By microinjecting fluorescently labeled histones into the syncytial embryo, the movements and divisions of each nucleus were recorded without perturbing development by using a microscope equipped with a high resolution, charge-coupled device. Two types of developmental maps were generated from three-dimensional time-lapse recordings: one traced the lineage history of each nucleus from nuclear cycle 11 through nuclear cycle 14 in a small region of the embryo; the other recorded nuclear fate according to the timing and pattern of the 14th nuclear division. By comparing these lineage and fate maps for two embryos, we conclude that, at least for the examined area, the pattern of mitotic domain formation in Drosophila is determined by the position of each cell, with no effect of cell lineage.

Delays in anaphase initiation occur in individual nuclei of the syncytial Drosophila embryo.

“…The Cytology of the Compound Chromosome C(2)EN The synthesis of C(2)EN by Novitski (1976) visions sink into the interior of the embryo leaving a nuclear free area on the surface (Minden et al, 1989;Sullivan et al, 1990Sullivan et al, , 1993. We have used this phenomenon to estimate the frequency of nuclear division errors during the syncytial blastoderm divisions.…”

“…We have examined the effects of an and rearranged compound second chr the rapid syncytial divisions of the em slower divisions of the larval neuro studies demonstrate that the presence chromosome dramatically increases ti syncytial embryonic divisions but has error rate in the later larval neuroblaz (Minden et al, 1989;Sullivan et al, 1990Sullivan et al, , 1993. v * Embryos bearing the C(2)EN chromosome exhibit a nuclear-division error frequency some 10-fold higher than embryos with a normal karyotype.…”

“…The in vivo analysis of the syncytial embryonic divisions was accomplished through a procedure in which fluorescently-labeled histones were microinjected into embryos (Kellogg et al, 1988;Minden et al, 1989;Sullivan et al, 1990). Observations and time lapse recordings were made on an Olympus IMT2 inverted microscope equipped with a Biorad MRC600 laser confocal imaging system.…”

“…The mitotic divisions of the early Drosophila embryo are synchronous, occurring in waves that initiate near the poles of the embryo. These divisions occur without cell growth or cytokinesis, and the G1 and G2 stages of the cell cycle are greatly reduced (Rabinowitz, 1941;Sonnenblick, 1950;Turner and Mahowald, 1976;Zalokar and Erk, 1976;Foe and Alberts, 1983;Minden et al, 1989). It has been suggested that the delays induced by checkpoints would not be compatible with these rapid synchronous divisions.…”

Three‐dimensional segmentation of nuclei and mitotic chromosomes for the study of cell divisions in live Drosophila embryos

“…Embryos, due to their transparency, and the availability of fluorescent reporter genes are especially amenable to imaging of division cycles in vivo. Fluorescently tagged fusion proteins enable visualization of the dynamics of chromosomes, microtubules, and other subcellular compartments (6)(7)(8). Early embryos show two types of division cycles.…”