Abstract
DNA fibre autoradiography of highly polytenized nuclei in salivary glands of Drosophila nasuta larvae reveals two distinct types of active replicons. Type I replicons are longer (mean size=64 μm), have a very high rate of fork migration (average rate=0.95 μm/min) and generally occur in large arrays often extending over several thousand μm. In contrast, the type II replicons are smaller (mean size= 20 μm), slow replicating (average rate=0.07 μm/min) and occur in short arrays containing only a few closely spaced active replicons. Evidence is presented that type I replicons are active in the early S and type II in the late S. Observations on autoradiographic labelling of partially lysed polytene chromosomes provide evidence for a lack of temporal and spatial agreement in the activation of origin points in homologous regions of the lateral polytene strands; these observations also suggest local variations in levels of polyteny within a chromosome. On the basis of this and other available information on replication in polytene chromosomes the possible roles of the two replicon types in the generation of the different 3H-thymidine labelling patterns of polytene chromosomes are discussed.
Similar content being viewed by others
References
Achary PMR, Majumdar K, Duttagupta A, Mukherjee AS (1981) Replication of DNA in larval salivary glands of Drosophila after in vivo synchronization. Chromosoma 82:505–514
Ananiev EV, Polukarova LG, Yurov YB (1977) Replication of chromosomal DNA in diploid Drosophila melanogaster cells cultured in vitro. Chromosoma 59:259–272
Arcos-Terán L (1972) DNS-Replikation and die Natur der spätreplizierenden Orte im X-Chromosom von Drosophila melanogaster. Chromosoma 37:233–296
Beermann W (1972) Chromomeres and genes. In: Beermann W, Reinert J, Ursprung H (eds) Results and problems in cell differentiation. Vol 4 Springer Verlag, Berlin Heidelberg New York, pp 1–33
Blumenthal AB, Kriegstein HJ, Hogness DS (1973) The units of DNA replication in Drosophila melanogaster chromosomes. Cold Spring Harbor Symp Quant Biol 27:205–223
Callan HG (1972) Replication of DNA in chromosomes of eukaryotes. Proc R Soc Lond Ser B 181:19–41
Cowell JK, Hartmann-Goldstein IJ (1980) Contrasting response of euchromatin and heterochromatin to translocation in polytene chromosomes of Drosophila melanogaster. Chromosoma 79:329–340
Hägele K (1973) Complementäre DNA-Replikationmuster bei Drosophila melanogaster. Chromosoma 41:231–236
Hand R (1979) Eukaryotic chromosome replication and its regulation. In: Prescott DM, Goldstein L (eds) Cell biology: A comprehensive treatise. Vol 2. Academic Press, New York San Francisco London. pp 389–437
Kalisch W-E, Hägele K (1973) Different DNA replication behaviour of a tandem duplication in Drosophila melanogaster, Chromosoma 44:265–283
Laird CD (1980) Structural paradox of polytene chromosomes. Cell 22:869–874
Lakhotia SC, Mukherjee AS (1970) Chromosomal basis of dosage compensation in Drosophila III. Early completion of replication by the polytene X chromosome in males: further evidence and its implications. J Cell Biol 47:18–33
Mishra A, Lakhotia SC (1982a) Replication in Drosophila chromosomes. VII. Influence of prolonged larval life on patterns of replication in polytene chromosomes of Drosophila melanogaster. Chromosoma 85:221–236
Mishra A, Lakhotia SC (1982b) Replication in Drosophila chromosomes. VIII. Temporal order of replication of specific sites in polytene chromosomes from 24° C and 10° C reared larvae of D. melanogaster. Ind J Exp Biol 20:652–659
Mukherjee AS, Beermann W (1965) Synthesis of ribonucleic acid by the X chromosome of Drosophila melanogaster and the problem of dosage compensation. Nature 207:785–786
Mulder MP, van Duijn P, Gloor HJ (1968) The replicative organization of DNA in polytene chromosomes of Drosophila hydei. Genetica 39:385–428
Roberts PA (1979) Rapid change in chromomeric pairing patterns of polytene chromosome tips in D. melanogaster: Migration of polytene — non-polytene transition zones? Genetics 92:861–878
Rodman TC (1968) Relationship of developmental stages to initiation of replication in polytene nuclei. Chromosoma 23:271–287
Roy S, Lakhotia SC (1981) Replication in Drosophila chromosomes. IV. Patterns of chromosomal replication in salivary gland polytene nuclei of D. nasuta. Ind J Exp Biol 19:797–807
Rudkin GT (1972) Replication in polytene chromosomes. In: Beermann W, Reinert J, Ursprung H (eds) Results and problems in cell differentiation. Vol 4 Springer Verlag, Berlin Heidelberg New York, pp 58–85
Sass H (1980) Hierarchy of fibrillar organization levels in the polytene interphase chromosomes of Chironomus. J Cell Sci 45:269–293
Sinha P, Lakhotia SC (1980) Replication in Drosophila chromosomes. V. Polytene chromosome replication after in vitro culture of larval salivary glands. Ind J Exp Biol 18:1059–1065
Sinha P, Lakhotia SC (1983) Replication in Drosophila chromosomes. IX. Stimulation of initiation of polytene replication cycles in vitro by juvenile hormone. Cell Differ 12:11–17
Sorsa V, Virrankoski-Castrodeza V (1976) Whole mount electron microscopy of alkali-urea treated polytene chromosomes spread by centrifugation. Hereditas 82:131–135
Steinemann M (1981a) Chromosomal replication in Drosophila virilis. II. Organization of active origins in diploid brain cells. Chomosoma 82:267–288
Steinemann M (1981b) Chromosomal replication in Drosophila virilis. III. Organization of active origins in the highly polytene salivary gland cells. Chromosoma 82:289–307
Taylor JH (1977) Increase in DNA replication sites in cells held at the beginning of S phase. Chromosoma 62:291–300
Taylor JH (1978) Control of initiation of DNA replication in mammalian cells. In: Molineux I, Kohiyama M (eds) DNA synthesis: Present and future. Plenum Publishing Corp, New York, pp 143–159
Yurov YB (1979) The rate of fork movement during DNA replication in mammalian cells. Chromosoma 74:347–353
Author information
Authors and Affiliations
Additional information
We take pleasure in dedicating this paper to our inspiring teacher Prof. S.P. Ray Chaudhuri on his completing 75 years of fruitful life
Rights and permissions
About this article
Cite this article
Lakhotia, S.C., Sinha, P. Replication in Drosophila chromosomes. Chromosoma 88, 265–276 (1983). https://doi.org/10.1007/BF00292903
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00292903