Factors involved in the expression of gene activity in polytene chromosomes

Berendes, H. D.

doi:10.1007/bf00285017

Cited by 160 publications

(32 citation statements)

References 13 publications

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“…In such analyses, contradictory results have been obtained with tandem array systems: inhibition of transcription had little effect on VP16 tandem arrays (40) but induced the recondensation of MMTV arrays (23). In classical systems, transcription is required for the decondensation of lampbrush chromosomes (22) and for normal puffing of genes in polytene chromosomes (2,6).…”

Section: Resultsmentioning

confidence: 99%

“…This is likely to be the norm, since it is also seen in the MMTV tandem array that uses a natural promoter (23) as well as with most genes examined in puffs or lampbrush chromosomes (2,6). The one clear exception to this rule are lac tandem arrays, which do not require transcription for maintaining the decondensed state (40).…”

Section: Vol 24 2004 Generic Features Of Tertiary Chromatin Structumentioning

confidence: 99%

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Generic Features of Tertiary Chromatin Structure as Detected in Natural Chromosomes

Müller

Rieder

Kreth

et al. 2004

Molecular and Cellular Biology

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Knowledge of tertiary chromatin structure in mammalian interphase chromosomes is largely derived from artificial tandem arrays. In these model systems, light microscope images reveal fibers or beaded fibers after high-density targeting of transactivators to insertional domains spanning several megabases. These images of fibers have lent support to chromonema fiber models of tertiary structure. To assess the relevance of these studies to natural mammalian chromatin, we identified two different ϳ400-kb regions on human chromosomes 6 and 22 and then examined light microscope images of interphase tertiary chromatin structure when the regions were transcriptionally active and inactive. When transcriptionally active, these natural chromosomal regions elongated, yielding images characterized by a series of adjacent puncta or "beads", referred to hereafter as beaded images. These elongated structures required transcription for their maintenance. Thus, despite marked differences in the density and the mode of transactivation, the natural and artificial systems showed similarities, suggesting that beaded images are generic features of transcriptionally active tertiary chromatin. We show here, however, that these images do not necessarily favor chromonema fiber models but can also be explained by a radial-loop model or even a simple nucleosome affinity, random-chain model. Thus, light microscope images of tertiary structure cannot distinguish among competing models, although they do impose key constraints: chromatin must be clustered to yield beaded images and then packaged within each cluster to enable decondensation into adjacent clusters.Chromatin structure can be classified hierarchically (44). Primary structure refers to the organization of DNA on nucleosomes, for example, the 10-nm fiber. Secondary structures arise from interactions between nucleosomes, for example, the 30-nm fiber. Tertiary structures are formed by interactions between secondary structures, and quaternary structures are formed by interactions between tertiary structures. Thus, tertiary and quaternary structures can involve the organized compaction of the chromatin fiber over domains of hundreds of kilobases (16). Here we use the term "tertiary structure " to refer generally to all higher-order chromatin structures beyond the level of the 30-nm fiber.

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Section: Resultsmentioning

confidence: 99%

Section: Vol 24 2004 Generic Features Of Tertiary Chromatin Structumentioning

confidence: 99%

Generic Features of Tertiary Chromatin Structure as Detected in Natural Chromosomes

Müller

Rieder

Kreth

et al. 2004

Molecular and Cellular Biology

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“…Storage of newly synthesized R N A has been considered to be one of the characteristics of the puff (4). The most plausible hypothesis, taking into account these findings and those obtained in other species (6), is that the increase of incorporation of [aH]uridine observed in section X15E of the salivary gland chromosomes of T. pubescens, after diethyl ether anesthesia, is due to an increase in gene transcription at this region. Thus, this treatment brings about the induction or increase of gene transcription at specific chromosomal loci.…”

Section: Discussionmentioning

confidence: 62%

Experimental induction of gene activity in the salivary gland chromosomes of Trichosia pubescens (Diptera: Sciaridae).

Amabis¹,

Janczur²

1978

The Journal of Cell Biology

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During the course of experiments with larvae of Trichosia pubescens, we have unexpectedly found that diethyl ether or chloroform anesthesia induces a large puff in a specific band in the polytene chromosomes of the salivary glands. This puff develops a few minutes after the treatment, attaining its maximum size after 60-100 min, and regresses completely 200 min after its activation. Through autoradiography, an intense incorporation of RNA precursors into that puff was observed. A few other smaller puffs are also induced by the treatment. The treatment with diethyl ether or chloroform does not induce puffing in the polytene cells of malpighian tubules and of midgut.KEY WORDS gene activity polytene chromosomes RNA synthesis diethyl ether chloroformSince the pioneer works on the puffing phenomenon in polytene chromosomes, a considerable amount of circumstantial evidence has supported the idea, first proposed by Beermann (2, 3) and by Breuer and Pavan (13,14), that the puffs are the morphological expression of gene activity (for a review, see references 1 and 8).Nowadays it is possible to characterize biochemically the products of a single puff (10,11,15,20) and to gather information on puff ultrastructure (5, 16, 24). Thus, puffs offer unique opportunities for the investigation of the process of gene activation and deactivation in eucaryotes.Of particular interest are the puffs that can be experimentally induced and/or repressed. They allow the study of factors involved in the regulation of the puffing phenomenon, as well as the establishment of correlations between individual puffs and specific changes in cell metabolism. This is exemplified by recent studies on Drosophila, which have provided information about the nature of the RNA produced in specific puffs (9,10,12,19,22,23) and the changes in cellular metabolism after puff induction (9,17,18,25).During the course of experiments with larvae of T. pubescens, we have unexpectedly found that diethyl ether or chloroform anesthesia induces, within a few minutes, the development of a large puff in a specific band of the salivary gland polytene chromosomes. This paper describes the kinetics of formation and regression of this puff. In addition, some features of RNA synthesis and nonhistone protein accumulation in the corresponding chromosome region, both in the unpuffed and in the puffed condition, are presented. MATERIALS AND METHODSFemale larvae of Trichosia pubescens (Diptera, Sciaridae) at two stages of larval development were used in the experiments. Larvae from stage L1 (midfourth instar)J. CELL BIOLOGY 9 The Rockefeller University Press 9

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“…Either this peptide is not encoded for by a heat-shock locus, and indeed only in the case of the 70000-M, peptide do we have any direct evidence that this peptide is a product of one of the heat-shock loci (namely 2-36 A [28]), or alternatively the gene for this protein could be located closely linked to one of the heat-shock-sensitive sites. Furthermore, autoradiography of pulse-labelled heat-shocked salivary gland chromosomes has shown a high background activity over the whole genome [26] while, after hybridization in situ, sites other than the heat-shockloci are labelled ( [27,28] and unpublished observation) suggesting that a number of additional loci are transcribed. These sites may code for some of the minor proteins.…”

Section: Discussionmentioning

confidence: 93%

Heat‐Shock Peptides in Drosophila hydei and Their Synthesis in vitro

Sondermeijer

Lubsen

1978

European Journal of Biochemistry

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The protein‐synthetic response to a heat shock, namely the synthesis of a number of new peptides, of Drosophila hydei salivary glands and tissue‐culture cells appears qualitatively the same when analyzed by dodecylsulphate electrophoresis, except that in tissue‐culture cells an additional band at 25500 Mr appears while the 20000‐Mr peptide, found in salivary glands, is sometimes absent depending on the cell line used. Further analysis of the heat‐shock peptides by two‐dimensional electrophoresis showed that the response of salivary glands and embryonic cells also differs: two major proteins with a molecular weight around 26000 were found in embryos, one of which may be identical to the 25500‐Mr protein seen in cultured cells. Two‐dimensional heat‐shock patterns are further characterized by a number of minor polypeptides whose position and intensity vary slightly from one tissue to another. Polysomal poly(A)‐containing RNA extracted from heat‐shocked embryos and tissue‐culture cells directed the synthesis in a wheat germ extract of all heat‐shock peptides found in vivo in the same tissue. Therefore, the appearance of one additional protein in embryos and tissue‐culture cells does not arise from tissue‐specific post‐translational modifications but must be due to the induction of an additional gene as compared to salivary glands. A similar conclusion may hold for the minor heat‐shock proteins found in the two‐dimensional patterns in vivo as well as in vitro.

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Factors involved in the expression of gene activity in polytene chromosomes

Cited by 160 publications

References 13 publications

Generic Features of Tertiary Chromatin Structure as Detected in Natural Chromosomes

Generic Features of Tertiary Chromatin Structure as Detected in Natural Chromosomes

Experimental induction of gene activity in the salivary gland chromosomes of Trichosia pubescens (Diptera: Sciaridae).

Heat‐Shock Peptides in Drosophila hydei and Their Synthesis in vitro

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