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Dynamics of endoreplication during Drosophila posterior scutellar macrochaete development.

Kawamori A, Shimaji K, Yamaguchi M - PLoS ONE (2012)

Bottom Line: We also found that the timing of endoreplication differs, depending on the type of macrochaete.Moreover, endocycling in shaft cells of both the left and right sides of pSC bristle lineages occurs in the same pattern, indicating that the process is synchronized for specific types of macrochaete.Our findings suggest that endocycling in macrochaete cell lineages can be a model for understanding mechanisms of endoreplication at the single-cell level.

View Article: PubMed Central - PubMed

Affiliation: Department of Applied Biology, Kyoto Institute of Technology, Sakyo-ku, Kyoto, Japan.

ABSTRACT
Endoreplication is a variant type of DNA replication, consisting only of alternating G1 and S phases. Many types of Drosophila tissues undergo endoreplication. However, the timing and the extent to which a single endocycling macrochaete undergoes temporally programmed endoreplication during development are unclear. Here, we focused on the dynamics of endoreplication during posterior scutellar (pSC) macrochaete development. Quantitative analyses of C values in shaft cells and socket cells revealed a gradual rise from 8C and 4C at 8 hours after pupal formation (APF) to 72C and 24C at 29 hours APF, respectively. The validity of the values was further confirmed by the measurement of DNA content with a confocal laser microscope. BrdU incorporation assays demonstrated that shaft cells undergo four rounds of endoreplication from 18 to 29.5 hours APF. In contrast, socket cells undergo two rounds of endoreplication during the same period. Statistical analyses showed that the theoretical C values, based on BrdU assays, nearly coincide with the actually measured C values in socket cells, but not in shaft cells after 22 hours APF. These analyses suggest that socket cells undergo two rounds of endoreplication. However, the mechanism of endoreplication in the shaft cells may change from 22 hours APF, suggesting the possibility that shaft cells undergo two or four rounds of endoreplication during the periods. We also found that the timing of endoreplication differs, depending on the type of macrochaete. Moreover, endocycling in shaft cells of both the left and right sides of pSC bristle lineages occurs in the same pattern, indicating that the process is synchronized for specific types of macrochaete. Our findings suggest that endocycling in macrochaete cell lineages can be a model for understanding mechanisms of endoreplication at the single-cell level.

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The endocycle is synchronized in pSC macrochaetes.Wild type pupae were grown until particular times of development and BrdU incorporation assays were performed as described in the Materials and Methods. The Y axis indicates % of pupae in which BrdU signals were simultaneously detected in pSC shaft cells of both left and right sides of a thorax. Sample numbers are shown at the top of each bar.
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pone-0038714-g005: The endocycle is synchronized in pSC macrochaetes.Wild type pupae were grown until particular times of development and BrdU incorporation assays were performed as described in the Materials and Methods. The Y axis indicates % of pupae in which BrdU signals were simultaneously detected in pSC shaft cells of both left and right sides of a thorax. Sample numbers are shown at the top of each bar.

Mentions: The patterns of BrdU incorporation in pSC shaft and socket cells appear to be almost identical in both the left and right side of the thorax (Table S1), suggesting that endocycling is synchronized in pSC macrochaetes. To further confirm the hypothesis, we reanalyzed the pre-existing data (Fig. 4 and Table S1) and counted the pSC shaft cells that are simultaneously BrdU-positive on both left and right sides of an adult thorax at 17.5, 21, 22.5, 26.5 and 29 hours APF. High ratios of pSC shaft cells that are simultaneously BrdU-positive on both sides were observed at several stages of development (Fig. 5) (in detail, 46% at 17.5, 78% at 21, 67% at 22.5, 48% at 26.5 and 70% at 28 hours APF). The results strongly support the hypothesis that endocycling is synchronized in pSC macrochaetes.


Dynamics of endoreplication during Drosophila posterior scutellar macrochaete development.

Kawamori A, Shimaji K, Yamaguchi M - PLoS ONE (2012)

The endocycle is synchronized in pSC macrochaetes.Wild type pupae were grown until particular times of development and BrdU incorporation assays were performed as described in the Materials and Methods. The Y axis indicates % of pupae in which BrdU signals were simultaneously detected in pSC shaft cells of both left and right sides of a thorax. Sample numbers are shown at the top of each bar.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3368872&req=5

pone-0038714-g005: The endocycle is synchronized in pSC macrochaetes.Wild type pupae were grown until particular times of development and BrdU incorporation assays were performed as described in the Materials and Methods. The Y axis indicates % of pupae in which BrdU signals were simultaneously detected in pSC shaft cells of both left and right sides of a thorax. Sample numbers are shown at the top of each bar.
Mentions: The patterns of BrdU incorporation in pSC shaft and socket cells appear to be almost identical in both the left and right side of the thorax (Table S1), suggesting that endocycling is synchronized in pSC macrochaetes. To further confirm the hypothesis, we reanalyzed the pre-existing data (Fig. 4 and Table S1) and counted the pSC shaft cells that are simultaneously BrdU-positive on both left and right sides of an adult thorax at 17.5, 21, 22.5, 26.5 and 29 hours APF. High ratios of pSC shaft cells that are simultaneously BrdU-positive on both sides were observed at several stages of development (Fig. 5) (in detail, 46% at 17.5, 78% at 21, 67% at 22.5, 48% at 26.5 and 70% at 28 hours APF). The results strongly support the hypothesis that endocycling is synchronized in pSC macrochaetes.

Bottom Line: We also found that the timing of endoreplication differs, depending on the type of macrochaete.Moreover, endocycling in shaft cells of both the left and right sides of pSC bristle lineages occurs in the same pattern, indicating that the process is synchronized for specific types of macrochaete.Our findings suggest that endocycling in macrochaete cell lineages can be a model for understanding mechanisms of endoreplication at the single-cell level.

View Article: PubMed Central - PubMed

Affiliation: Department of Applied Biology, Kyoto Institute of Technology, Sakyo-ku, Kyoto, Japan.

ABSTRACT
Endoreplication is a variant type of DNA replication, consisting only of alternating G1 and S phases. Many types of Drosophila tissues undergo endoreplication. However, the timing and the extent to which a single endocycling macrochaete undergoes temporally programmed endoreplication during development are unclear. Here, we focused on the dynamics of endoreplication during posterior scutellar (pSC) macrochaete development. Quantitative analyses of C values in shaft cells and socket cells revealed a gradual rise from 8C and 4C at 8 hours after pupal formation (APF) to 72C and 24C at 29 hours APF, respectively. The validity of the values was further confirmed by the measurement of DNA content with a confocal laser microscope. BrdU incorporation assays demonstrated that shaft cells undergo four rounds of endoreplication from 18 to 29.5 hours APF. In contrast, socket cells undergo two rounds of endoreplication during the same period. Statistical analyses showed that the theoretical C values, based on BrdU assays, nearly coincide with the actually measured C values in socket cells, but not in shaft cells after 22 hours APF. These analyses suggest that socket cells undergo two rounds of endoreplication. However, the mechanism of endoreplication in the shaft cells may change from 22 hours APF, suggesting the possibility that shaft cells undergo two or four rounds of endoreplication during the periods. We also found that the timing of endoreplication differs, depending on the type of macrochaete. Moreover, endocycling in shaft cells of both the left and right sides of pSC bristle lineages occurs in the same pattern, indicating that the process is synchronized for specific types of macrochaete. Our findings suggest that endocycling in macrochaete cell lineages can be a model for understanding mechanisms of endoreplication at the single-cell level.

Show MeSH