While Drosophila female meiosis is anastral, both meiotic divisions in Drosophila males exhibit prominent asters. We have identified a gene we call asterless (asl) that is required for aster formation during male meiosis. Ultrastructural analysis showed that asl mutants have morphologically normal centrioles. However, immunostaining with antibodies directed either to g tubulin or centrosomin revealed that these proteins do not accumulate in the centrosomes, as occurs in wild-type. Thus, asl appears to specify a function required for the assembly of centrosomal material around the centrioles. Despite the absence of asters, meiotic cells of asl mutants manage to develop an anastral spindle. Microtubules grow from multiple sites around the chromosomes, and then focus into a peculiar bipolar spindle that mediates chromosome segregation, although in a highly irregular way. Surprisingly, asl spermatocytes eventually form a morphologically normal ana–telophase central spindle that has full ability to stimulate cytokinesis. These findings challenge the classical view on central spindle assembly, arguing for a self-organization of this structure from either preexisting or newly formed microtubules. In addition, these findings strongly suggest that the asters are not required for signaling cytokinesis.

Spindle self-organization and cytokinesis during male meiosis in asterless mutants of Drosophila melanogaster / Bonaccorsi, Silvia; M. G., Giansanti; Gatti, Maurizio. - In: THE JOURNAL OF CELL BIOLOGY. - ISSN 0021-9525. - STAMPA. - 142:3(1998), pp. 751-761. [10.1083/jcb.142.3.751]

Spindle self-organization and cytokinesis during male meiosis in asterless mutants of Drosophila melanogaster

BONACCORSI, Silvia;GATTI, MAURIZIO
1998

Abstract

While Drosophila female meiosis is anastral, both meiotic divisions in Drosophila males exhibit prominent asters. We have identified a gene we call asterless (asl) that is required for aster formation during male meiosis. Ultrastructural analysis showed that asl mutants have morphologically normal centrioles. However, immunostaining with antibodies directed either to g tubulin or centrosomin revealed that these proteins do not accumulate in the centrosomes, as occurs in wild-type. Thus, asl appears to specify a function required for the assembly of centrosomal material around the centrioles. Despite the absence of asters, meiotic cells of asl mutants manage to develop an anastral spindle. Microtubules grow from multiple sites around the chromosomes, and then focus into a peculiar bipolar spindle that mediates chromosome segregation, although in a highly irregular way. Surprisingly, asl spermatocytes eventually form a morphologically normal ana–telophase central spindle that has full ability to stimulate cytokinesis. These findings challenge the classical view on central spindle assembly, arguing for a self-organization of this structure from either preexisting or newly formed microtubules. In addition, these findings strongly suggest that the asters are not required for signaling cytokinesis.
1998
centrosome; cytokinesis; drosophila; male meiosis; spindle assembly
01 Pubblicazione su rivista::01a Articolo in rivista
Spindle self-organization and cytokinesis during male meiosis in asterless mutants of Drosophila melanogaster / Bonaccorsi, Silvia; M. G., Giansanti; Gatti, Maurizio. - In: THE JOURNAL OF CELL BIOLOGY. - ISSN 0021-9525. - STAMPA. - 142:3(1998), pp. 751-761. [10.1083/jcb.142.3.751]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/243817
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