Developmental Regulation of DNA-Topoisomerases during Drosophila Embryogenesis

Mark J. Gemkow; Joachim Dichter; Donna J. Arndt-Jovin

doi:10.1006/excr.2000.5084

Developmental Regulation of DNA-Topoisomerases during Drosophila Embryogenesis

Experimental Cell Research ◽

10.1006/excr.2000.5084 ◽

2001 ◽

Vol 262 (2) ◽

pp. 114-121 ◽

Cited By ~ 5

Author(s):

Mark J. Gemkow ◽

Joachim Dichter ◽

Donna J. Arndt-Jovin

Keyword(s):

Developmental Regulation ◽

Dna Topoisomerases ◽

Drosophila Embryogenesis

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Zygotic expression of the pebble locus is required for cytokinesis during the postblastoderm mitoses of Drosophila

Development ◽

10.1242/dev.114.1.165 ◽

1992 ◽

Vol 114 (1) ◽

pp. 165-171 ◽

Cited By ~ 5

Author(s):

G. Hime ◽

R. Saint

Keyword(s):

Drosophila Melanogaster ◽

Developmental Regulation ◽

Single Cells ◽

Embryonic Cell ◽

Cell Cycles ◽

Drosophila Embryogenesis ◽

Zygotic Transcription ◽

Homozygous Mutant ◽

Mitotic Figures

Mutations at the pebble locus of Drosophila melanogaster result in embryonic lethality. Examination of homozygous mutant embryos at the end of embryogenesis revealed the presence of fewer and larger cells which contained enlarged nuclei. Characterization of the embryonic cell cycles using DAPI, propidium iodide, anti-tubulin and anti-spectrin staining showed that the first thirteen rapid syncytial nuclear divisions proceeded normally in pebble mutant embryos. Following cellularization, the postblastoderm nuclear divisions occurred (mitoses 14, 15 and 16), but cytokinesis was never observed. Multinucleate cells and duplicate mitotic figures were seen within single cells at the time of the cycle 15 mitoses. We conclude that zygotic expression of the pebble gene is required for cytokinesis following cellularization during Drosophila embryogenesis. We postulate that developmental regulation of zygotic transcription of the pebble gene is a consequence of the transition from syncytial to cellular mitoses during cycle 14 of embryogenesis.

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The regulation of the cell cycle during Drosophila embryogenesis: the transition to polyteny

Development ◽

10.1242/dev.112.4.997 ◽

1991 ◽

Vol 112 (4) ◽

pp. 997-1008 ◽

Cited By ~ 29

Author(s):

A.V. Smith ◽

T.L. Orr-Weaver

Keyword(s):

Cell Cycle ◽

Dna Replication ◽

Developmental Regulation ◽

Mitotic Cell ◽

Mitotic Cell Cycle ◽

Drosophila Embryogenesis ◽

First Instar ◽

Late Embryogenesis ◽

Gap Phase ◽

Different Tissues

The process of polytenization plays a crucial role in Drosophila development, and most of the larval tissues are polytene. By analyzing the pattern of DNA replication in embryos pulse-labeled with BrdU, we show that many larval tissues undergo a transition to begin becoming polytene late in embryogenesis. Our results demonstrate that in these larval tissues polyteny results from a modified cell cycle, the endo cell cycle, in which there is only an S (synthesis) phase and a G (gap) phase. A key regulator of the mitotic cell cycle, the product of the string gene (the Drosophila homologue of cdc25), is not required for the endo cell cycle. The developmental regulation of the endo cell cycle is striking in that tissue-specific domains undergo polytene DNA replication in a dynamic pattern at defined times in embryogenesis. During subsequent rounds of the endo cell cycle in late embryogenesis and first instar larval development, the domains are subdivided and the temporal control is not as rigid. The length of the G phase varies among different tissues. By quantifying DNA content, we show that during the early polytene S phases the genome is not fully duplicated.

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