Hormonal control of gene amplification and transcription in the salivary gland chromosomes of Trichosia pubescens

Amabis, Dulce Cabral; Amabis, J M

doi:10.1016/0012-1606(84)90170-2

Cited by 22 publications

(6 citation statements)

References 13 publications

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“…It appears that Ec, along with EcR, is necessary as a sutained stimulus at least at some DNA puff sites. Some earlier ligation experiments with R. americana and in vitro studies with Trichosia support this notion (Amabis et al 1977; J. Ferreira, unpublished results; discussed in Amabis and Amabis 1984b). Based on the results obtained in the present and above-cited investigations, we suggest that initial binding of the Ec-EcR complex to many DNA puff loci stimulates a low level of transcription, which might facilitate amplification and eventually proceeds to puffing.…”

Section: Discussionsupporting

confidence: 83%

“…The only consistent signal in larvae of this stage was at an RNA puff site that regresses during L2. During late L3, DNA amplification begins simultaneously at all the DNA puff sites (Amabis and Amabis 1984b). In our L3 slides, we could see increased density of certain bands, indicating that amplification had begun.…”

Section: Patterns Of Asce/d Reaction At Dna Puff Sitesmentioning

confidence: 93%

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Antibodies against the D-domain of a Chironomus ecdysone receptor protein react with DNA puff sites in Trichosia pubescens

et al. 1997

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An antiserum (called AScE/D) against the semiconserved D-domain of a Chironomus tentans ecdysone receptor protein (cEcR) gave indirect immunofluorescence signals at DNA puff sites in Trichosia pubescens. The signals varied in maximum intensity at different DNA puff sites. Control experiments using the secondary rhodamine-labeled anti-rabbit IgG alone, preimmune serum, affinity purified AScE/D (called pABcE/D) and AScE/D preabsorbed with expressing bacterial extract or highly purified bacterially expressed cEcR indicated that the signals obtained at these chromosomal sites were likely to be due to specific interaction between an endogenous sciarid EcR and antibodies against cEcR. This conclusion was supported by observation of signals at certain Ec-inducible primary RNA puff sites. AScE/D signals began to appear at DNA puff sites during L3, the stage when amplification initiates, but at most sites their mean intensity was low and not statistically significant. Sites with AScE/D signals of significant mean intensity at this stage already showed evidence of transcription. The number and strength of transcription signals increased during L4. Comparison of the developmental course of signals for AScE/D, DNA synthesis, RNA presence/synthesis, and puff size for several DNA puffs during late larval- prepupal development showed a closer relationship of AScE/D signals with the initiation of RNA synthesis than with the initiation of DNA synthesis. Therefore, although we cannot absolutely eliminate a direct involvement of EcR in the amplification process at some sites, this investigation gives stronger support for its direct involvement in transcription. Since AScE/D signals are observed at DNA puff sites from the time the latter begin amplification/transcription through their regression, it appears that Ec and EcR are necessary as a sustained stimulus at these regions.

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Section: Discussionsupporting

confidence: 83%

Section: Patterns Of Asce/d Reaction At Dna Puff Sitesmentioning

confidence: 93%

Antibodies against the D-domain of a Chironomus ecdysone receptor protein react with DNA puff sites in Trichosia pubescens

et al. 1997

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“…A strong candidate for the activation of the BhB10-1 gene at the end of the larval stage is ecdysone which is known to regulate DNA puffing in sciarid polytene chromosomes (25)(26)(27)(28), and which induces DNA puff B10 formation when injected into early larvae (Fontes AM and Paçó-Larson ML, unpublished data). The observation of a peak in the ecdysteroid titer approximately 26 h before the pupal molt in B. hygida (Hartfelder K, Basso Jr LR and Paçó-Larson ML, unpublished data) also agrees with the idea that the induction of BhB10-1 mRNA expression in all tissues of late larvae may be regulated by ecdysone.…”

Section: Discussionmentioning

confidence: 99%

The DNA puff BhB10-1 gene is differentially expressed in various tissues of Bradysia hygida late larvae and constitutively transcribed in transgenic Drosophila

Monesi

Sousa

Paçó-Larson

2001

Braz J Med Biol Res

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We extended the characterization of the DNA puff BhB10-1 gene of Bradysia hygida by showing that, although its mRNA is detected only at the end of the fourth larval instar, BhB10-1 expression is not restricted to the salivary gland, the tissue in which this gene is amplified. Different amounts of BhB10-1 mRNA were detected in other larval tissues such as gut, Malpighian tubules, fat body, brain and cuticle, suggesting that this gene is expressed differentially in the various tissues analyzed. Analysis of transgenic Drosophila carrying the BhB10-1 transcription unit and flanking sequences revealed that the tested fragment promotes transcription in a constitutive manner. We suggest that either cis-regulatory elements are missing in the transgene or factors that temporally regulate the BhB10-1 gene in B. hygida are not conserved in Drosophila.

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“…On the other hand, the maintenance of long‐term cultures in the laboratory has been challenging and nowadays these species are only sporadically available in nature. T. pubescens can be raised in the laboratory and several landmark papers in the field of sciarid biology have employed this species as a model (Amabis and Amabis, ; Amabis and Cabral, ). However, the molecular characterization of amplified domains is limited in T. pubescens as compared to other sciarids.…”

Section: The Future Of Sciaridsmentioning

confidence: 99%

Beyond DNA puffs: What can we learn from studying sciarids?

Simon

Siviero

Monesi

2016

Genesis

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Members of the Sciaridae family attracted the interest of researchers because of the demonstration that the DNA puff regions, which are formed in the salivary gland polytene chromosomes at the end of the fourth larval instar, constitute sites of developmentally regulated gene amplification. Besides contributing to a deeper understanding of the process of gene amplification, the study of sciarids has also provided important insights on other biological processes such as sex determination, programmed cell death, insect immunity, telomere maintenance, and nucleolar organizing regions (NOR) formation. Open questions in sciarids include among others, early development, the role of noncoding RNAs in gene amplification and the relationship between gene amplification and transcription in DNA puff forming regions. These and other questions can now be pursued with next generation sequencing techniques and experiments using RNAi experiments, since this latter technique has been shown to be feasible in sciarids. These new perspectives in the field of sciarid biology open the opportunity to consolidate sciarid species as important emerging models. genesis 54:361-378, 2016. © 2016 Wiley Periodicals, Inc.

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Hormonal control of gene amplification and transcription in the salivary gland chromosomes of Trichosia pubescens

Cited by 22 publications

References 13 publications

Antibodies against the D-domain of a Chironomus ecdysone receptor protein react with DNA puff sites in Trichosia pubescens

Antibodies against the D-domain of a Chironomus ecdysone receptor protein react with DNA puff sites in Trichosia pubescens

The DNA puff BhB10-1 gene is differentially expressed in various tissues of Bradysia hygida late larvae and constitutively transcribed in transgenic Drosophila

Beyond DNA puffs: What can we learn from studying sciarids?

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