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Regulation of centromere localization of the Drosophila Shugoshin MEI-S332 and sister-chromatid cohesion in meiosis.

Nogueira C, Kashevsky H, Pinto B, Clarke A, Orr-Weaver TL - G3 (Bethesda) (2014)

Bottom Line: These studies also suggested that MEI-S332 can be inactivated independently of delocalization, a conclusion supported here by localization and function studies in meiosis.Phosphoresistant and phosphomimetic mutants for the Aurora B and Polo phosphorylation sites were examined for effects on MEI-S332 localization and chromosome segregation in meiosis.Strikingly, MEI-S332 with a phosphomimetic mutation in the Aurora B phosphorylation site prematurely dissociates from the centromeres in meiosis I.

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Affiliation: Whitehead Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142.

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In vivo localization of the MEI-S332T331-A mutant protein. (A) Localization of MEI-S332T331-A in meiosis I and II. Labels, colors, and scale bars as in Figure 1. A late anaphase I spermatocyte is shown. The dotted lines in the meiosis II panels demarcate two metaphase II and two telophase II spermatocytes. (B) Quantification of MEI-S332T331-A localization. Spermatocyte numbers scored were: metaphase I (n = 21), anaphase I (n = 22), metaphase II (n = 11), anaphase II (n = 17), and telophase II (n = 65). This mutant protein localizes and delocalizes from centromeres with proper timing in meiosis I spermatocytes, although in contrast to wild type, we did not observe the protein along chromosome arms in early anaphase I. We did not detect the protein localized on the anaphase II chromosomes.
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fig4: In vivo localization of the MEI-S332T331-A mutant protein. (A) Localization of MEI-S332T331-A in meiosis I and II. Labels, colors, and scale bars as in Figure 1. A late anaphase I spermatocyte is shown. The dotted lines in the meiosis II panels demarcate two metaphase II and two telophase II spermatocytes. (B) Quantification of MEI-S332T331-A localization. Spermatocyte numbers scored were: metaphase I (n = 21), anaphase I (n = 22), metaphase II (n = 11), anaphase II (n = 17), and telophase II (n = 65). This mutant protein localizes and delocalizes from centromeres with proper timing in meiosis I spermatocytes, although in contrast to wild type, we did not observe the protein along chromosome arms in early anaphase I. We did not detect the protein localized on the anaphase II chromosomes.

Mentions: To test the localization properties and function of the T331-A mutant in meiosis, we produced transgenic lines in which this form of MEI-S332-GFP was expressed from the endogenous promoter at levels comparable to wild type (Figure S2). This protein was localized in spermatocytes lacking wild-type MEI-S332. The results contrasted with those obtained in cell culture in that the protein was delocalized from centromeres at the metaphase II/anaphase II transition (Figure 4). Nondisjunction assays were used to quantify the function of MEI-S332T331-A in chromosome segregation. This mutant protein also restored sister-chromatid segregation to mei-S332 mutants (Table 2).


Regulation of centromere localization of the Drosophila Shugoshin MEI-S332 and sister-chromatid cohesion in meiosis.

Nogueira C, Kashevsky H, Pinto B, Clarke A, Orr-Weaver TL - G3 (Bethesda) (2014)

In vivo localization of the MEI-S332T331-A mutant protein. (A) Localization of MEI-S332T331-A in meiosis I and II. Labels, colors, and scale bars as in Figure 1. A late anaphase I spermatocyte is shown. The dotted lines in the meiosis II panels demarcate two metaphase II and two telophase II spermatocytes. (B) Quantification of MEI-S332T331-A localization. Spermatocyte numbers scored were: metaphase I (n = 21), anaphase I (n = 22), metaphase II (n = 11), anaphase II (n = 17), and telophase II (n = 65). This mutant protein localizes and delocalizes from centromeres with proper timing in meiosis I spermatocytes, although in contrast to wild type, we did not observe the protein along chromosome arms in early anaphase I. We did not detect the protein localized on the anaphase II chromosomes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4199692&req=5

fig4: In vivo localization of the MEI-S332T331-A mutant protein. (A) Localization of MEI-S332T331-A in meiosis I and II. Labels, colors, and scale bars as in Figure 1. A late anaphase I spermatocyte is shown. The dotted lines in the meiosis II panels demarcate two metaphase II and two telophase II spermatocytes. (B) Quantification of MEI-S332T331-A localization. Spermatocyte numbers scored were: metaphase I (n = 21), anaphase I (n = 22), metaphase II (n = 11), anaphase II (n = 17), and telophase II (n = 65). This mutant protein localizes and delocalizes from centromeres with proper timing in meiosis I spermatocytes, although in contrast to wild type, we did not observe the protein along chromosome arms in early anaphase I. We did not detect the protein localized on the anaphase II chromosomes.
Mentions: To test the localization properties and function of the T331-A mutant in meiosis, we produced transgenic lines in which this form of MEI-S332-GFP was expressed from the endogenous promoter at levels comparable to wild type (Figure S2). This protein was localized in spermatocytes lacking wild-type MEI-S332. The results contrasted with those obtained in cell culture in that the protein was delocalized from centromeres at the metaphase II/anaphase II transition (Figure 4). Nondisjunction assays were used to quantify the function of MEI-S332T331-A in chromosome segregation. This mutant protein also restored sister-chromatid segregation to mei-S332 mutants (Table 2).

Bottom Line: These studies also suggested that MEI-S332 can be inactivated independently of delocalization, a conclusion supported here by localization and function studies in meiosis.Phosphoresistant and phosphomimetic mutants for the Aurora B and Polo phosphorylation sites were examined for effects on MEI-S332 localization and chromosome segregation in meiosis.Strikingly, MEI-S332 with a phosphomimetic mutation in the Aurora B phosphorylation site prematurely dissociates from the centromeres in meiosis I.

View Article: PubMed Central - PubMed

Affiliation: Whitehead Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142.

Show MeSH
Related in: MedlinePlus