Electron microscope autoradiographic study on transcriptional activity of Drosophila melanogaster polytene chromosomes

The ribosomal protein uL11 is located at the basis of the ribosome P-stalk and plays a paramount role in translation efficiency. In addition, no mutant for uL11 is available suggesting that this gene is haplo-insufficient as many other Ribosomal Protein Genes (RPGs). We have previously shown that overexpression of Drosophila melanogaster uL11 induces the transcription of many RPGs and Ribosomal Biogenesis genes (RiBis) suggesting that uL11 might globally regulate the level of translation through its transcriptional activity. Moreover, uL11 trimethylated on lysine 3 (uL11K3me3) interacts with the chromodomain of the Enhancer of Polycomb and Trithorax Corto. uL11, Corto and RNA Polymerase II co-localize at many sites on polytene chromosomes. These data have led to the hypothesis that the N-terminal end of uL11, and more particularly the trimethylation of lysine 3, supports the extra-ribosomal activity of uL11 in transcription. To address this question, we mutated the lysine 3 codon using a CRISPR/Cas9 strategy and obtained several lysine 3 mutants. We describe here the first mutants of Drosophila melanogaster uL11. Unexpectedly, the uL11K3A allele, in which the lysine 3 codon is replaced by an alanine, displays a genuine Minute phenotype known to be characteristic of RPG deletions (longer development, low fertility, high lethality, thin and short bristles) whereas the uL11K3Y allele, in which the lysine 3 codon is replaced by a tyrosine, is unaffected. In agreement, the translation rate slightly decreases in uL11K3A but not in uL11K3Y. Deep-sequencing of RNA from wing imaginal discs shows enrichment in the GO categories glutathione metabolism for up-regulated genes in both mutants and regulation of transcription for down-regulated genes in uL11K3A. Furthermore, analysis of deregulated genes cis-regulatory sequences suggests that uL11 might regulate transcription of target genes in concert with the couple of transcription factors Mad/Med that mediate response to the Bone Morphogenetic Protein (BMP) signaling pathway.

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Electron microscope investigation of polytene chromosomes in the Mediterranean fruit fly Ceratitis capitata

Genome ◽

10.1139/g95-083 ◽

1995 ◽

Vol 38 (4) ◽

pp. 652-660 ◽

Cited By ~ 9

Author(s):

V. F. Semeshin ◽

I. F. Zhimulev ◽

D. Kritikou ◽

A. Zacharopoulou

Keyword(s):

Electron Microscopy ◽

Electron Microscope ◽

Salivary Glands ◽

X Chromosome ◽

Transcriptional Activity ◽

Ceratitis Capitata ◽

Polytene Chromosomes ◽

Fruit Fly ◽

Electron Microscope Investigation ◽

Rnp Granules

Ultrastructural analyses of polytene chromosomes from male pupal orbital bristle cells and from larval salivary glands of Ceratitis capitata were carried out. It was shown that chromatin complexes corresponding to the X chromosome heterochromatic network are surrounded by material containing ribonucleoprotein (RNP) granules 250–300 Å (1 Å = 0.1 nm) in diameter. RNP granules of similar size surround the spherical Y chromosome. These data point out the presence of transcriptional activity in both of these chromosomes. The absence of clear structure in chromosomal regions situated between large bands in both types of tissues was observed. These results support the hypothesis of weak synapsis between chromatids or small chromomeres of polytene chromosomes in this species. In addition, we describe a specific puff revealed in both orbital trichogen cells and salivary glands that is morphologically similar to the 93D puff of Drosophila melanogaster.Key words: Ceratitis capitata, polytene chromosomes, electron microscopy.

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Mutational Analysis of a Histone Deacetylase in Drosophila melanogaster: Missense Mutations Suppress Gene Silencing Associated With Position Effect Variegation

Genetics ◽

10.1093/genetics/154.2.657 ◽

2000 ◽

Vol 154 (2) ◽

pp. 657-668 ◽

Cited By ~ 2

Author(s):

Randy Mottus ◽

Richard E Sobel ◽

Thomas A Grigliatti

Keyword(s):

Drosophila Melanogaster ◽

Histone Deacetylase ◽

Transcriptional Activity ◽

Mutational Analysis ◽

Position Effect ◽

Transcriptional Regulator ◽

Position Effect Variegation ◽

Missense Mutations ◽

Effect Variegation ◽

New Mutations

Abstract For many years it has been noted that there is a correlation between acetylation of histones and an increase in transcriptional activity. One prediction, based on this correlation, is that hypomorphic or null mutations in histone deacetylase genes should lead to increased levels of histone acetylation and result in increased levels of transcription. It was therefore surprising when it was reported, in both yeast and fruit flies, that mutations that reduced or eliminated a histone deacetylase resulted in transcriptional silencing of genes subject to telomeric and heterochromatic position effect variegation (PEV). Here we report the first mutational analysis of a histone deacetylase in a multicellular eukaryote by examining six new mutations in HDAC1 of Drosophila melanogaster. We observed a suite of phenotypes accompanying the mutations consistent with the notion that HDAC1 acts as a global transcriptional regulator. However, in contrast to recent findings, here we report that specific missense mutations in the structural gene of HDAC1 suppress the silencing of genes subject to PEV. We propose that the missense mutations reported here are acting as antimorphic mutations that “poison” the deacetylase complex and propose a model that accounts for the various phenotypes associated with lesions in the deacetylase locus.

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Chromosomal Distribution of Transposable Elements in Drosophila melanogaster Test of the Ectopic Recombination Model for Maintenance of Insertion Site Number

Genetics ◽

10.1093/genetics/144.1.197 ◽

1996 ◽

Vol 144 (1) ◽

pp. 197-204

Author(s):

Christine Hoogland ◽

Christian Biémont

Keyword(s):

Drosophila Melanogaster ◽

Transposable Elements ◽

Dna Content ◽

Recombination Rate ◽

Alternative Hypothesis ◽

Insertion Site ◽

Polytene Chromosomes ◽

Negative Relationship ◽

Site Occupancy ◽

Site Number

Abstract Data of insertion site localization and site occupancy frequency of P, hobo, I, copia, mdg1, mdg3, 412, 297, and roo transposable elements (TEs) on the polytene chromosomes of Drosophila melanogaster were extracted from the literature. We show that TE insertion site number per chromosomal division was significantly correlated with the amount of DNA. The insertion site number weighted by DNA content was not correlated with recombination rate for all TEs except hobo, for which a positive correlation was detected. No global tendency emerged in the relationship between TE site occupancy frequency, weighted by DNA content, and recombination rate; a strong negative correlation was, however, found for the 3L arm. A possible dominant deleterious effect of chromosomal rearrangements due to recombination between TE insertions is thus not the main factor explaining the dynamics of TEs, since this hypothesis implies a negative relationship between recombination rate and both TE insertion site number and site occupancy frequency. The alternative hypothesis of selection against deleterious effects of insertional mutations is discussed.

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A quantitative electron microscope autoradiographic study on 125I-human choriogonadotropin internalization in bovine luteal slices

Experimental Cell Research ◽

10.1016/0014-4827(84)90397-5 ◽

1984 ◽

Vol 151 (2) ◽

pp. 483-493 ◽

Cited By ~ 7

Author(s):

N. Chegini ◽

Ch.V. Rao ◽

G. Cobbs

Keyword(s):

Electron Microscope ◽

Autoradiographic Study ◽

Human Choriogonadotropin

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Microdissection and cloning of DNA from a specific region of Drosophila melanogaster polytene chromosomes

Chromosoma ◽

10.1007/bf00286105 ◽

1981 ◽

Vol 82 (2) ◽

pp. 205-216 ◽

Cited By ~ 214

Author(s):

F. Scalenghe ◽

E. Turco ◽

J. E. Edström ◽

V. Pirrotta ◽

M. Melli

Keyword(s):

Drosophila Melanogaster ◽

Polytene Chromosomes ◽

Specific Region

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The in vitro uptake and distribution of3H-fucose and3H-mannose in the crayfish retina: A light and electron microscope autoradiographic study

Journal of Experimental Zoology ◽

10.1002/jez.1402310205 ◽

1984 ◽

Vol 231 (2) ◽

pp. 199-210 ◽

Cited By ~ 4

Author(s):

G. S. Hafner

Keyword(s):

Electron Microscope ◽

Autoradiographic Study ◽

In Vitro Uptake

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Ultrastructure of polytene chromosomes of Drosophila isolated by microdissection

Journal of Cell Science ◽

10.1242/jcs.45.1.15 ◽

1980 ◽

Vol 45 (1) ◽

pp. 15-30

Author(s):

M.R. Mott ◽

E.J. Burnett ◽

R.J. Hill

Keyword(s):

Electron Microscope ◽

Polytene Chromosomes ◽

Ultrastructural Level ◽

Chromosomal Proteins ◽

Linear Arrays ◽

Ribonucleoprotein Particles ◽

Acid Protein

Drosophila polytene chromosomes prepared by a new micromanipulative procedure, which avoids acid squashing, have been examined at the ultrastructural level in the electron microscope. Puffs at 2B, 68C, 74EF, 75B and 85EF, have been examined in some detail, along with the chromocentre and various interbands. The ultrastructure of these chromosomes, which have never been exposed to acid protein denaturants, compares favourably with that of classical acid-fixed specimens. Ribonucleoprotein particles in puffs are seen to be organized in linear arrays and evidence is adduced for looped transcription units. Particles with characteristic sizes and morphologies are observed near the chromocentre, in puffs and in interbands. In interbands RNP particles and ‘superbead’-like chromatin particles may be distinguished. Drosophila polytene chromosomes isolated by micro-manipulation should prove useful for the localization of native chromosomal proteins at an ultrastructural level.

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A cDNA from Drosophila melanogaster encodes a lamin C-like intermediate filament protein

Journal of Cell Science ◽

10.1242/jcs.104.4.1263 ◽

1993 ◽

Vol 104 (4) ◽

pp. 1263-1272 ◽

Cited By ~ 4

Author(s):

C.A. Bossie ◽

M.M. Sanders

Keyword(s):

Drosophila Melanogaster ◽

Intermediate Filament ◽

Blot Analysis ◽

Polytene Chromosomes ◽

Intermediate Filament Protein ◽

Chromosome 2 ◽

Cross Hybridization ◽

Intermediate Filament Proteins ◽

Nuclear Lamins ◽

Filament Protein

A novel intermediate filament cDNA, pG-IF, has been isolated from a Drosophila melanogaster embryonic expression library screened with a polyclonal antiserum produced against a 46 kDa cytoskeletal protein isolated from Kc cells. This 46 kDa protein is known to be immunologically related to vertebrate intermediate filament proteins. The screen resulted in the isolation of four different cDNA groups. Of these, one has been identified as the previously characterized Drosophila nuclear lamin cDNA, Dm0, and a second, pG-IF, demonstrates homology to Dm0 by cross hybridization on Southern blots. DNA sequence analysis reveals that pG-IF encodes a newly identified intermediate filament protein in Drosophila. Its nucleotide sequence is highly homologous to nuclear lamins with lower homology to cytoplasmic intermediate filament proteins. pG-IF predicts a protein of 621 amino acids with a predicted molecular mass of 69,855 daltons. In vitro transcription and translation of pG-IF yielded a protein with a SDS-PAGE estimated molecular weight of approximately 70 kDa. It contains sequence principles characteristic of class V intermediate filament proteins. Its near neutral pI (6.83) and the lack of a terminal CaaX motif suggests that it may represent a lamin C subtype in Drosophila. In situ hybridization to polytene chromosomes detects one band of hybridization on the right arm of chromosome 2 at or near 51A. This in conjunction with Southern blot analysis of various genomic digests suggests one or more closely placed genes while Northern blot analysis detects two messages in Kc cells.

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