Chromosomes initiate spindle assembly upon experimental dissolution of the nuclear envelope in grasshopper spermatocytes.
Open Access
- 1 December 1995
- journal article
- Published by Rockefeller University Press in The Journal of cell biology
- Vol. 131 (5), 1125-1131
- https://doi.org/10.1083/jcb.131.5.1125
Abstract
Chromosomes are known to enhance spindle microtubule assembly in grasshopper spermatocytes, which suggested to us that chromosomes might play an essential role in the initiation of spindle formation. Chromosomes might, for example, activate other spindle components such as centrosomes and tubulin subunits upon the breakdown of the nuclear envelope. We tested this possibility in living grasshopper spermatocytes. We ruptured the nuclear envelope during prophase, which prematurely exposed the centrosomes to chromosomes and nuclear sap. Spindle assembly was promptly initiated. In contrast, assembly of the spindle was completely inhibited if the nucleus was mechanically removed from a late prophase cell. Other experiments showed that the trigger for spindle assembly is associated with the chromosomes; other constituents of the nucleus cannot initiate spindle assembly in the absence of the chromosomes. The initiation of spindle assembly required centrosomes as well as chromosomes. Extracting centrosomes from late prophase cells completely inhibited spindle assembly after dissolution of the nuclear envelope. We conclude that the normal formation of a bipolar spindle in grasshopper spermatocytes is regulated by chromosomes. A possible explanation is an activator, perhaps a chromosomal protein (Yeo, J.-P., F. Alderuccio, and B.-H. Toh. 1994a. Nature (Lond.). 367: 288-291), that promotes and stabilizes the assembly of astral microtubules and thus promotes assembly of the spindle.Keywords
This publication has 27 references indexed in Scilit:
- The impact of chromosomes and centrosomes on spindle assembly as observed in living cells.The Journal of cell biology, 1995
- A new chromosomal protein essential for mitotic spindle assemblyNature, 1994
- Mitotic spindle assembly by two different pathways in vitro.The Journal of cell biology, 1991
- Micromanipulated bivalents can trigger mini-spindle formation in Drosophila melanogaster spermatocyte cytoplasm.The Journal of cell biology, 1986
- The reproduction of centrosomes: nuclear versus cytoplasmic controls.The Journal of cell biology, 1986
- Beyond self-assembly: From microtubules to morphogenesisCell, 1986
- Aster-free spindle poles in insect spermatocytes: evidence for chromosome-induced spindle formation?The Journal of cell biology, 1986
- Experimental separation of pronuclei in fertilized sea urchin eggs: chromosomes do not organize a spindle in the absence of centrosomes.The Journal of cell biology, 1985
- Spindle microtubules and their mechanical associations after micromanipulation in anaphase.The Journal of cell biology, 1982
- SPINDLE MICROTUBULES: THERMODYNAMICS OF IN VIVO ASSEMBLY AND ROLE IN CHROMOSOME MOVEMENT*Annals of the New York Academy of Sciences, 1975