scholarly journals Effects of Mutations in the Drosophila melanogaster Rif1 Gene on the Replication and Underreplication of Pericentromeric Heterochromatin in Salivary Gland Polytene Chromosomes

Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1501
Author(s):  
Tatyana D. Kolesnikova ◽  
Alexandra V. Kolodyazhnaya ◽  
Galina V. Pokholkova ◽  
Veit Schubert ◽  
Viktoria V. Dovgan ◽  
...  
Keyword(s):  
Salivary Gland ◽  
Satellite Dna ◽  
Polytene Chromosomes ◽  
Replication Timing ◽  
Wild Type ◽  
Chromosome X ◽  
Substantial Fraction ◽  
In The Wild ◽  
Specific Control

In Drosophila salivary gland polytene chromosomes, a substantial portion of heterochromatin is underreplicated. The combination of mutations SuURES and Su(var)3-906 results in the polytenization of a substantial fraction of unique and moderately repeated sequences but has almost no effect on satellite DNA replication. The Rap1 interacting factor 1 (Rif) protein is a conserved regulator of replication timing, and in Drosophila, it affects underreplication in polytene chromosomes. We compared the morphology of pericentromeric regions and labeling patterns of in situ hybridization of heterochromatin-specific DNA probes between wild-type salivary gland polytene chromosomes and the chromosomes of Rif1 mutants and SuUR Su(var)3-906 double mutants. We show that, despite general similarities, heterochromatin zones exist that are polytenized only in the Rif1 mutants, and that there are zones that are under specific control of Su(var)3-9. In the Rif1 mutants, we found additional polytenization of the largest blocks of satellite DNA (in particular, satellite 1.688 of chromosome X and simple satellites in chromosomes X and 4) as well as partial polytenization of chromosome Y. Data on pulsed incorporation of 5-ethynyl-2′-deoxyuridine (EdU) into polytene chromosomes indicated that in the Rif1 mutants, just as in the wild type, most of the heterochromatin becomes replicated during the late S phase. Nevertheless, a significantly increased number of heterochromatin replicons was noted. These results suggest that Rif1 regulates the activation probability of heterochromatic origins in the satellite DNA region.

scholarly journals UNDER-REPLICATION OF RIBOSOMAL CISTRONS IN POLYTENE CHROMOSOMES OF RHYNCHOSCIARA

1974 ◽  
Vol 62 (1) ◽  
pp. 215-222 ◽  
Author(s):  
A. G. Gambarini ◽  
F. J. S. Lara
Keyword(s):  
Salivary Gland ◽  
In Situ Hybridization ◽  
Xenopus Laevis ◽  
Related Species ◽  
Polytene Chromosomes ◽  
Chromosome X ◽  
Heterologous Hybridization ◽  
Ribosomal Cistrons ◽  
Rhynchosciara Americana

DNA preparations obtained from several tissues of Rhynchosciara americana and two related species, R. milleri and R. papaveroi, were hybridized to R. americana rRNA. The percentage of hybridization was found to be higher in tissues with low polyteny than in tissues with high polyteny, suggesting a relationship between the amount of rDNA and the tissue polyteny. This could be explained by under-replication of ribosomal cistrons in polytene cells, such as those from the salivary gland. Only slight tissue-dependent changes in the percentages of hybridization can be observed in heterologous hybridization using Xenopus laevis rRNA. The possibility that these experiments could not detect differences in the amount of ribosomal cistrons among tissues is discussed. The female:male ratio for the percentages of hybridization in the salivary gland of R. americana agrees with the results obtained by in situ hybridization experiments (16, 17) which have shown that the rRNA cistrons are distributed among chromosomes other than chromosome X.

The genome of the olive fruit fly Bactrocera oleae: localization of molecular markers by in situ hybridization to the salivary gland polytene chromosomes

Genome ◽  
1999 ◽  
Vol 42 (4) ◽  
pp. 744-751 ◽  
Author(s):  
Anna Zambetaki ◽  
Antigone Zacharopoulou ◽  
Zacharias G. Scouras ◽  
Penelope Mavragani-Tsipidou
Keyword(s):  
Salivary Gland ◽  
Molecular Markers ◽  
In Situ Hybridization ◽  
Polytene Chromosomes ◽  
Fruit Fly ◽  
Bactrocera Oleae ◽  
Olive Fruit Fly ◽  
Olive Fruit

The genome of the Mediterranean fruitflyceratitis capitata: Localization of molecular markers by in situ hybridization to salivary gland polytene chromosomes

Chromosoma ◽  
1992 ◽  
Vol 101 (7) ◽  
pp. 448-455 ◽  
Author(s):  
A. Zacharopoulou ◽  
M. Frisardi ◽  
C. Savakis ◽  
A. S. Robinson ◽  
P. Tolias ◽  
...  
Keyword(s):  
Salivary Gland ◽  
Molecular Markers ◽  
In Situ Hybridization ◽  
Polytene Chromosomes ◽  
The Mediterranean

scholarly journals Improving 3-methylphenol (m-cresol) production in yeast via in vivo glycosylation or methylation

2020 ◽  
Vol 20 (8) ◽  
Author(s):  
Julia Hitschler ◽  
Eckhard Boles
Keyword(s):  
Saccharomyces Cerevisiae ◽  
De Novo ◽  
Wild Type ◽  
Biotechnological Production ◽  
Yeast Saccharomyces Cerevisiae ◽  
In Situ Extraction ◽  
Methylsalicylic Acid Synthase ◽  
In The Wild

ABSTRACT Heterologous expression of 6-methylsalicylic acid synthase (MSAS) together with 6-MSA decarboxylase enables de novo production of the platform chemical and antiseptic additive 3-methylphenol (3-MP) in the yeast Saccharomyces cerevisiae. However, toxicity of 3-MP prevents higher production levels. In this study, we evaluated in vivo detoxification strategies to overcome limitations of 3-MP production. An orcinol-O-methyltransferase from Chinese rose hybrids (OOMT2) was expressed in the 3-MP producing yeast strain to convert 3-MP to 3-methylanisole (3-MA). Together with in situ extraction by dodecane of the highly volatile 3-MA this resulted in up to 211 mg/L 3-MA (1.7 mM) accumulation. Expression of a UDP-glycosyltransferase (UGT72B27) from Vitis vinifera led to the synthesis of up to 533 mg/L 3-MP as glucoside (4.9 mM). Conversion of 3-MP to 3-MA and 3-MP glucoside was not complete. Finally, deletion of phosphoglucose isomerase PGI1 together with methylation or glycosylation and feeding a fructose/glucose mixture to redirect carbon fluxes resulted in strongly increased product titers, with up to 897 mg/L 3-MA/3-MP (9 mM) and 873 mg/L 3-MP/3-MP as glucoside (8.1 mM) compared to less than 313 mg/L (2.9 mM) product titers in the wild type controls. The results show that methylation or glycosylation are promising tools to overcome limitations in further enhancing the biotechnological production of 3-MP.

Primed in situ labeling (PRINS): a method for rapid identification and quantification of human chromosomes in both lymphocytes and sperm nuclei

Genome ◽  
1998 ◽  
Vol 41 (5) ◽  
pp. 739-741 ◽  
Author(s):  
Antonio Musio ◽  
Paolo Baroli ◽  
Isabella Sbrana
Keyword(s):  
Satellite Dna ◽  
Human Sperm ◽  
Rapid Identification ◽  
Human Chromosomes ◽  
Chromosome X ◽  
Specific Primer ◽  
Sperm Nuclei ◽  
Identification And Quantification

In this work, a specific primer for X alphoid satellite DNA was used to detect chromosome X through primed in situ labeling (PRINS). The method allows the rapid identification of chromosome X in metaphase and its quantification in interphase. PRINS is equally applicable to both lymphocytes and sperm nuclei.Key words: PRINS, human sperm, chromosome X.

scholarly journals The Drosophila salivary gland chromocenter contains highly polytenized subdomains of mitotic heterochromatin.

Genetics ◽  
1995 ◽  
Vol 139 (2) ◽  
pp. 659-670 ◽  
Author(s):  
P Zhang ◽  
A C Spradling
Keyword(s):  
Salivary Gland ◽  
Dna Sequences ◽  
Polytene Chromosomes ◽  
Centromeric Heterochromatin ◽  
Mitotic Chromosomes ◽  
Satellite Dnas ◽  
Central Mass ◽  
P Elements

Abstract Peri-centromeric regions of Drosophila melanogaster chromosomes appear heterochromatic in mitotic cells and become greatly underrepresented in giant polytene chromosomes, where they aggregate into a central mass called the chromocenter. We used P elements inserted at sites dispersed throughout much of the mitotic heterochromatin to analyze the fate of 31 individual sites during polytenization. Analysis of DNA sequences flanking many of these elements revealed that middle repetitive or unique sequence DNAs frequently are interspersed with satellite DNAs in mitotic heterochromatin. All nine Y chromosome sites tested were underrepresented > 20-fold on Southern blots of polytene DNA and were rarely or never detected by in situ hybridization to salivary gland chromosomes. In contrast, nine tested insertions in autosomal centromeric heterochromatin were represented fully in salivary gland DNA, despite the fact that at least six were located proximal to known blocks of satellite DNA. The inserted sequences formed diverse, site-specific morphologies in the chromocenter of salivary gland chromosomes, suggesting that domains dispersed at multiple sites in the centromeric heterochromatin of mitotic chromosomes contribute to polytene beta-heterochromatin. We suggest that regions containing heterochromatic genes are organized into dispersed chromatin configurations that are important for their function in vivo.

scholarly journals Neuronal Chloride Accumulation in Olfactory Epithelium of Mice Lacking NKCC1

2006 ◽  
Vol 95 (3) ◽  
pp. 2003-2006 ◽  
Author(s):  
William T. Nickell ◽  
Nancy K. Kleene ◽  
Robert C. Gesteland ◽  
Steven J. Kleene
Keyword(s):  
Olfactory Epithelium ◽  
Electrical Response ◽  
Niflumic Acid ◽  
Olfactory Receptor Neurons ◽  
Flufenamic Acid ◽  
Wild Type ◽  
In The Wild ◽  
Receptor Neurons ◽  
Chloride Accumulation

When stimulated with odorants, olfactory receptor neurons (ORNs) produce a depolarizing receptor current. In isolated ORNs, much of this current is caused by an efflux of Cl−. This implies that the neurons have one or more mechanisms for accumulating cytoplasmic Cl− at rest. Whether odors activate an efflux of Cl− in intact olfactory epithelium, where the ionic environment is poorly characterized, has not been previously determined. In mouse olfactory epithelium, we found that >80% of the summated electrical response to odors is blocked by niflumic acid or flufenamic acid, each of which inhibits Ca2+-activated Cl− channels in ORNs. This indicates that ORNs accumulate Cl− in situ. Recent evidence has shown that NKCC1, a Na+-K+-2Cl− cotransporter, contributes to Cl− accumulation in mammalian ORNs. However, we find that the epithelial response to odors is only reduced by 39% in mice carrying a null mutation in Nkcc1. As in the wild-type, most of the response is blocked by niflumic acid or flufenamic acid, indicating that the underlying current is carried by Cl−. We conclude that ORNs effectively accumulate Cl− in situ even in the absence of NKCC1. The Cl−-transport mechanism underlying this accumulation has not yet been identified.

The 3-D substructure of RNA in nascent RNP granules: A novel application of osmium ammine-B staining and electron spectroscopic imaging

1992 ◽  
Vol 50 (1) ◽  
pp. 504-505
Author(s):  
Ada L. Olins ◽  
Donald E. Olins ◽  
Manesh B. Shah ◽  
Henri A. Levy ◽  
David P. Bazett-Jonest
Keyword(s):  
Salivary Gland ◽  
Polytene Chromosomes ◽  
Spectroscopic Imaging ◽  
Secretory Proteins ◽  
Chironomus Tentans ◽  
Balbiani Ring ◽  
Electron Spectroscopic Imaging ◽  
Nuclear Pores ◽  
Rnp Granules

RNA has a particulate substructure when visualized in situ with the nucleic acid specific stain osmium ammine-B (OA-B). In this study energy spectroscopic imaging (ESI) was used to enhance the contrast and collect the data for tomographic reconstructions.The Balbiani ring (BR) in the salivary gland polytene chromosomes of Chironomus tentans larvae furnishes a well known model for the structure of nascent m-RNA. This gland produces copious amounts of silk-like secretory proteins which are very large (106 daltons). The site of transcription, the BR, is easily recognized in the EM by its characteristic “puff” structure and electron-dense granular transcripts. Mature BR granules are 45-50 nm in diameter and can be easily observed within the nucleus and passing through nuclear pores.

The genome of the olive fruit fly Bactrocera oleae: localization of molecular markers by in situ hybridization to the salivary gland polytene chromosomes

Genome ◽  
1999 ◽  
Vol 42 (4) ◽  
pp. 744-751 ◽  
Author(s):  
Anna Zambetaki ◽  
Antigone Zacharopoulou ◽  
Zacharias G Scouras ◽  
Penelope Mavragani-Tsipidou
Keyword(s):  
Salivary Gland ◽  
Molecular Markers ◽  
In Situ Hybridization ◽  
Polytene Chromosomes ◽  
Fruit Fly ◽  
Bactrocera Oleae ◽  
Olive Fruit Fly ◽  
Olive Fruit ◽  
Hybridization Mapping

Nine specific DNA probes (genomic or cDNA) from Ceratitis capitata have been mapped by in situ hybridization to the salivary gland polytene chromosomes of the olive fruit fly Bactrocera oleae, a major agricultural pest, thus establishing molecular markers for the 5 autosomal chromosomes. Taking into account the present results, as well as previous data obtained mainly by in situ hybridizations, chromosomal homologies among B. oleae, C. capitata and B. tryoni are established. Data show extensive linkage group conservation among the 3 taxa of the economically important and globally distributed family, the Tephritidae.Key words: Bactrocera oleae, Tephritidae, salivary gland, polytene chromosomes, in situ hybridization, mapping.

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