Microtubule disorientation in anaphase half-spindles during autosome segregation in crane fly spermatocytes
Tóm tắt
The region between the kinetochores of syntelically oriented autosomes and the pole in meta- and anaphase of Pales ferruginea spermatocytes was studied by means of serial sections. Microtubule (MT) were counted and measured, and the spindle region was reconstructed by superimposition of successive micrographs. Kinetochoric (kMTs) and non-kinetochoric microtubules (nkMTs) interdigitate with one another forming a bundle which is often arrow-shaped due to an inclination of nkMTs (skew nkMTs) with respect to the kinetochore-pole axis. The average length of MT in the bundle decreases towards anaphase while the average number increases. The extent of MT disorder in anaphase half-spindles is higher than in metaphase. The number of kMTs inserted in the kinetochore was found to remain unchanged from meta- to early anaphase. Some of the kMTs become divergent in anaphase. The relative proportion of skew nkMTs within the kMT/nkMT bundle is higher in anaphase. It is proposed that the morphological changes observed to occur from meta- to anaphase are due to fragmentation of kMTs followed by disorientation of the MTs pieces. Some aspects of the physical properties of the half-spindles are discussed.
Tài liệu tham khảo
Bajer, A.S.: Interaction of microtubules and the mechanism of chromosome movement (zipper hypothesis). 1. General principle. Cytobios 8, 139–160 (1973)
Bajer, A.S., Molè-Bajer, J., Lambert, A.-M.: Lateral interaction of microtubules and chromosome movements. In: Microtubules and Microtubule Inhibitors (M. Borgers and M. de Brabander, eds.), p. 393–423, Amsterdam 1975
Dietrich, J.: Reconstructions tridimensionelles de l'appareil mitotique à partir de coupes sériées longitudinales de méiocytes pollinique. Biol. cellulaire 34, 77–82 (1979)
Dietz, R.: Die Assembly-Hypothese der Chromosomenbewegung und die Veränderung der Spindellänge während der Anaphase I in Spermatocyten von Pales ferruginea (Tipulidae, Diptera). Chromosoma (Berl.) 38, 11–76 (1972)
Forer, A., Jackson, W.T., Engberg, A.: Actin in spindles of Haemanthus katherinae endosperm. II. Distribution of actin in chromosomal spindle fibres, determined by analysis of serial sections. J. Cell Sci. 37, 349–371 (1979)
Fuge, H.: Morphological studies on the structure of univalent sex chromosomes during anaphase movement in spermatocytes of the crane fly Pales ferruginea. Chromosoma (Berl.) 39, 403–417 (1972)
Fuge, H.: Verteilung der Mikrotubuli in Metaphase- und Anaphase-Spindeln der Spermatocyten von Pales ferruginea. Eine quantitative Analyse von Serienquerschnitten. Chromosoma (Berl.) 43, 109–143 (1973)
Fuge, H.: The arrangement of microtubules and the attachment of chromosomes to the spindle during anaphase in tipulid spermatocytes. Chromosoma (Berl.) 45, 245–260 (1974)
Fuseler, J.W.: Mitosis in Tilia americana endosperm. J. Cell Biol. 64, 159–171 (1975)
Hard, R., Allen, R.D.: Behaviour of kinetochore fibres in Haemanthus katherinae during anaphase movements of chromosomes. I. Cell Sci. 27, 47–56 (1977)
Izutsu, K., Sato, H., Nakabayashi, H., Aoki, N.: The behavior of spindle fibers and movement of chromosomes in dividing grasshopper spermatocytes. Cell Struct. Funct. 2, 119–133 (1977)
Jensen, C., Bajer, A.: Spindle dynamics and arrangement of microtubules. Chromosoma (Berl.) 44, 73–89 (1973)
LaFountain, J.R., Jr.: Analysis of birefringence and ultrastructure of spindles in primary spermatocytes of Nephrotoma suturalis during anaphase. J. Ultrastruct. Res. 54, 333–346 (1976)
Lambert, A.-M., Bajer, A.: Fine structure dynamics of the prometaphase spindle. J. Micr. Biol. Cell. 23, 181–194 (1975)
Lambert, A.-M., Bajer, A.: Microtubule distribution and reversible arrest of chromosome movements induced by low temperature. Cytobiologie 15, 1–23 (1977)
Mazia, D., Sale, W.S., Schatten, G.: Polylysine as an adhesive for electron microscopy. J. Cell Biol. 63, 212a (1974)
McIntosh, J.R., Hepler, P.K., Wie, D.G. van: Model for mitosis. Nature (Lond.) 224, 659–663 (1969)
McIntosh, J.R., Sisken, J.E., Chu, L.K.: Structural studies on mitotic spindles isolated from cultured human cells. J. Ultrastruct. Res. 66, 40–52 (1979)
Metz, C.W.: Monocentric mitosis with segregation of chromosomes in Sciara and its bearing on the mechanism of mitosis. Biol. Bull. 64, 333–347 (1933)
Moens, P.: Kinetochore microtubule numbers of different sized chromosomes. J. Cell Biol. (in press, 1979)
Tippit, D.H., Schulz, H., Pickett-Heaps, J.D.: Analysis of the distribution of spindle microtubules in the diatom Fragilaria. J. Cell Biol. 79, 737–763 (1978)
Wassermann, F.: Wachstum und Vermehrung der lebendigen Masse. Handb. mikrosk. Anat. d. Menschen, 1. Bd, 2. Teil. Berlin: Julius Springer 1929
Wassermann, F.: Mechanismus der Mitose. Arch. exp. Zellf. 22, 238–257 (1939)