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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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Model of dynamics of endoreplication during the development of pSC shaft and socket cells.Pattern of endoreplication and dynamic changes in C values in shaft and socket cells from 4 to 30 hours APF. Black boxes indicate S phases. Gray boxes indicate possible G1 phases. Patterns of BrdU incorporation in the periods indicated by Gray boxes with question marks were not determined.
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pone-0038714-g007: Model of dynamics of endoreplication during the development of pSC shaft and socket cells.Pattern of endoreplication and dynamic changes in C values in shaft and socket cells from 4 to 30 hours APF. Black boxes indicate S phases. Gray boxes indicate possible G1 phases. Patterns of BrdU incorporation in the periods indicated by Gray boxes with question marks were not determined.

Mentions: Our quantitative analyses provide the first demonstration of the dynamics of endoreplication during development of a single macrochaete (Fig. 4, see model in Fig. 7). We developed simple and quantitative methods to determine dynamic change in sizes and C values in shaft and socket cells (Fig. 1, 2). In combination with BrdU incorporation assays, a series of experiments demonstrated the following. (1) Endoreplication in shaft cells occurs at a higher frequency than that in socket cells (Fig. 3, 4, 7 and Table S1); (2) Timing of endoreplication in shaft cells differs from that in socket cells (Fig. 4, 7 and S1); (3) Endocycling in macrochaetes is synchronized (Fig. 4, 5, 6 and S1); (4) Patterns of endocycling differ, depending on the type of macrochaete (Fig. 4, 5, 6 and S1). These findings should contribute to a deeper understanding of the mechanisms of endocycling in macrochaete cell lineages.


Dynamics of endoreplication during Drosophila posterior scutellar macrochaete development.

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

Model of dynamics of endoreplication during the development of pSC shaft and socket cells.Pattern of endoreplication and dynamic changes in C values in shaft and socket cells from 4 to 30 hours APF. Black boxes indicate S phases. Gray boxes indicate possible G1 phases. Patterns of BrdU incorporation in the periods indicated by Gray boxes with question marks were not determined.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0038714-g007: Model of dynamics of endoreplication during the development of pSC shaft and socket cells.Pattern of endoreplication and dynamic changes in C values in shaft and socket cells from 4 to 30 hours APF. Black boxes indicate S phases. Gray boxes indicate possible G1 phases. Patterns of BrdU incorporation in the periods indicated by Gray boxes with question marks were not determined.
Mentions: Our quantitative analyses provide the first demonstration of the dynamics of endoreplication during development of a single macrochaete (Fig. 4, see model in Fig. 7). We developed simple and quantitative methods to determine dynamic change in sizes and C values in shaft and socket cells (Fig. 1, 2). In combination with BrdU incorporation assays, a series of experiments demonstrated the following. (1) Endoreplication in shaft cells occurs at a higher frequency than that in socket cells (Fig. 3, 4, 7 and Table S1); (2) Timing of endoreplication in shaft cells differs from that in socket cells (Fig. 4, 7 and S1); (3) Endocycling in macrochaetes is synchronized (Fig. 4, 5, 6 and S1); (4) Patterns of endocycling differ, depending on the type of macrochaete (Fig. 4, 5, 6 and S1). These findings should contribute to a deeper understanding of the mechanisms of endocycling in macrochaete cell lineages.

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