Chromosome puffs

Chromosome puff. A swollen region of a giant chromosome the swelling reflects a high degree of transcription activity. 

Dworniczak B., Kobus S., Schaltmann-Eiteljoerge K. and Pongs O. (1981) Ecdysterone, ecdysterone receptor, and chromosome puffs. In Gene Regulation by Steroid Hormones II, eds A. K. Roy and J. H. Clark, 1, 79-91. New York Springer-Verlag, 352 pp. 

Tissieres, A. H.K. Mitchell, and U.M. Tracy (1974). Protein synthesis in salivary glands of Drosophila melanogaster Relation to chromosome puffs. J. Mol. Biol. 84 389-398. 

Edstrom, J.-E., and W. Beermann. 1962. The base composition of nucleic acids in chromosomes, puffs, nucleoli and. cytoplasm of Chironomus salivary gland cells. J. Cell Biol., 14 371-380. 

A very clear picture of asynchrony and local heterogeneity of DNA synthesis in the chromosomes was obtained in studies of DNA synthesis in the polytene chromosomes of insect salivary glands. We shall describe the characteristics of synthesis of DNA, RNA, and proteins in these chromosomes in greater detail later in connection with our examination of chromosomal puffs. At this point, however, I shall mention the results of experiments (Plaut, 1963 Plaut and Nash, 1964) in which asynchrony of DNA synthesis in different parts of individual chromosomes was demonstrated very clearly. 

The simplest general scheme of morphogenesis of multicellular systems can thus be illustrated by the scheme shown in Fig. 101. This scheme is purely an illustrative, simplified model of differentiation. It is important to note, however, that processes similar to the patterns illustrated do in fact take place during actual development. I have in mind the ontogenesis of chromosomal puffs, i.e., the arrangement of zones of increased synthesis of RNA and proteins on cell chromosomes at the phases of development and during specialization along different lines. 

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