Abstract
This paper studies the process and features of chromosome construction in mitotic prophase cells of Allium cepa. The results showed that a prominent reorganization of chromatin occurred during G2-early prophase. The 250–400 nm thick compact chromatin threads in G2 nuclei began to disorganize into about 30, 100 and 220 nm chromatin fibres which constituted the loosely organized chromosome outlines in early prophase before chromosome condensation. In middle prophase, chromosome condensation was characterized by the formation of many condensed regions (aggregates of chromatin), which increased in size (1–1.5 μm) when prophase proceeded. Meanwhile, the chromatin threads that constituted and connected the condensed regions became increasingly thicker (120–250 nm). In late prophase adjacent condensed regions fused to form cylinder-shaped chromosomes. Based on these observations, we come to the conclusion that the construction of prophase chromosomes is a two-step process, that is, the reorganization and condensation of chromatin. In addition, we report the study of silver-stained, DNA- and histone-depleted prophase chromosomes, describe morphological features of the non-histone protein (NHP) residue in early, middle and late prophase chromosomes, and discuss the roles of NHPs in chromosome construction.
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Adolph KW, Cheng SM, Laemmli UK (1977) Role of nonhistone proteins on metaphase chromosome structure. Cell 12:805–812
Alberts B, Bray D, Lewis J, Raff M, Roberts K, Watson JD (1989) Molecular biology of the cell, 2nd edn. Garlang New York London, pp 762–767
Bekers AGM, Gijzev HJ, Taalman RDFM, Wanka F (1981) Ultrastructure of nuclear matrix from Physarum polycephalum during the mitotic cycle. J Ultrastruct Res 75:352–362
Bostock CJ, Sumner AT (1978) The eukaryotic chromosome, North-Holland, pp 288–290
Brachet J (1985) The cell cycle, molecular cytology, vol 1. Academic Press, New York, pp 263–264
Bradbury EM, Inglis RJ, Matthews HR (1974) Control of cell division by very lysine-rich histone (F1) phosphorylation. Nature 247:257–261
De la Torre C, Aacristan-Garate A, Navarrete MH (1975) Structural changes in chromatin during interphase. Chromosoma 51:183–198
Earnshaw WC, Laemmli UK (1983) Architecture of metaphase chromosomes and chromosome scaffolds. J Cell Biol 96:84–93
Earnshaw WC, Laemmli UK (1984) Silver staining of the chromosome scaffold. Chromosoma 89:186–192
Golomb HM, Bahr GF (1974) Human chromatin from interphase to metaphase. Exp Cell Res 84:79–87
Gurley LR, Walters RA, Tobey RA (1974) Cell cycle-specific changes in histone phosphorylation associated cell proliferation and chromosome condensation. J Cell Biol 60:356–364
Hao S, Xing M, Jiao M (1988) Chromatin-free compartments and their contents in anaphase chromosomes of higher plants. Cell Biol Int Rep 12:627–635
Hayles J, Nurse P (1989) A review of mitosis in the fission yeast Schizosaccharomyces pombe. Exp Cell Res 184:273–286
Henry S, Weinfeld H, Sandberg AA (1980) Effects of divalent cations and glucose on mitotic-like events in fused interphasemetaphase cells. Exp Cell Res 125:351–362
Howell WM, Black DA (1980) Controlled silver staining of nucleolar organizer regions with a protective colloidal developer: a 1-step method. Experientia 36:1014–1015
Howell WM, Hsu TC (1979) Chromosome core structure revealed by silver staining. Chromosoma 73:61–66
Inglis RJ, Langan TA, Matthews HR, Hardie DG, Bradbury EM (1976) Advance of mitosis by histone phosphokinase. Exp Cell Res 97:418–425
Laemmli UK, Cheng SM, Adolph KW, Paulson JR, Brown JA, Braumback WR (1978) Metaphase chromosome structure: the role of non-histone proteins. Cold Spring Harbor Symp Quant Biol 42:351–360
Lafontaine JG, Lord A (1974) An ultrastructural and radioautographic study of the evolution of the interphase nucleus in plant meristematic cells (Allium porrum). J Cell Sci 14:263–287
Lewis CD, Laemmli UK (1982) Higher order metaphase chromosome structure: evidence for metalloprotein interaction. Cell 29:171–181
Matsui SM, Weinfeld H, Sandberg AA (1982) Factors involved in prophasing and telophasing. In: Rao P, Johnson RT, Sperling K (eds) Premature chromosome condensation. Academic Press, New York, pp 207–232
Matsumoto Y, Yasuda H, Mita S, Marunouchi T, Yamada M (1980) Evidence for the involvement of H1 histone phosphorylation in chromosome condensation. Nature 284:181–183
Mullinger AM, Johnson R (1983) Units of chromosome replication and packing. J Cell Sci 64:179–193
Nagl W (1982) Condensed chromatin: species-specificity, tissuespecificity and cell cycle-specificity, as monitored by scanning cytometry. In: Nicolini C (ed) Cell growth. Plenum Press, New York, pp 171–218
Newport J, Spann T (1988) Disassembly of the nucleus in mitotic extracts: membrane vesicularization, lamin disassembly, and chromosome condensation are independent processes. Cell 48:219–230
Paulson JR, Laemmli UK (1977) The structure of histone-depleted metaphase chromosome. Cell 12:817–828
Rao PN, Johnson RT (1971) Mammalian cell fusion. IV. Regulation of chromosome formation from interphase nuclei by various chemical compounds. J Cell Physiol 78:217–224
Sorsa V (1973) Condensation of chromosomes during mitotic prophase. Hereditas 75:101–108
Sumner AT (1991) Scanning electron microscopy of mammalian chromosomes from prophase to telophase. Chromosoma 100:410–418
Uemura T, Ohkura H, Adachi Y, Morino K, Shiozaki K (1987) DNA Topoisomerase II is required for condensation and separation of mitotic chromosomes in S. pombe. Cell 50:917–925
Xing M, Hao S (1989) RNP structure in metaphase chromosome of Vicia faba. Science in China (Ser B) 32:706–712
Yunis JJ, Bahr GF (1979) Chromatin fibre organization of human interphase and prophase chromosomes. Exp Cell Res 122:63–72
Zhao J, Hao S, Xing M (1991) The fine structure of the mitotic chromosome core (scaffold) of Trilophidia annulata. Chromosoma 100:323–329
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Hao, S., Jiao, M., Zhao, J. et al. Reorganization and condensation of chromatin in mitotic prophase nuclei of Allium cepa . Chromosoma 103, 432–440 (1994). https://doi.org/10.1007/BF00362288
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DOI: https://doi.org/10.1007/BF00362288