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Journal of Insect Science (Online) May 2022Drosophila E74 is an early gene located in the polytene chromosome 74EF puff position. E74 controls the production of late genes, indicating that it plays a crucial role...
Drosophila E74 is an early gene located in the polytene chromosome 74EF puff position. E74 controls the production of late genes, indicating that it plays a crucial role in this cascade model. Nilaparvata lugens E74 is closely related to Diaphorina citri, Bemisia tabaci, and Laodelphax striatellus. After downregulating E74, molting, and nymphal mortality were increased, and ovarian development was delayed. Moreover, the expression of Vg was reduced at the transcriptional level, as measured by qRT-PCR, and the content of Vg protein was reduced, as detected by Western blotting. After downregulating E74, the expression of hormone-related genes, including Tai, βFtz-F1, Met, Kr-h1, UspA, UspB, E93, and Br, was changed. The expression of E74 was significantly decreased after downregulating hormone-related genes. When the expression of E74 and βFtz-F1 was downregulated together, nymph mortality and molting mortality were higher than those when E74 or βFtz-F1 was downregulated alone. Thus, E74 probably interacts with βFtz-F1 at the genetic level. In summary, this study showed that E74 plays a crucial role in the development, metamorphosis and reproduction of N. lugens, possibly via the interaction with βFtz-F1 at the genetic level. This study provides a basis for the development of new target-based pesticides and new methods for the effective control of N. lugens.
Topics: Animals; Drosophila; Drosophila Proteins; Hemiptera; Hormones; Metamorphosis, Biological; Nymph
PubMed: 35738261
DOI: 10.1093/jisesa/ieac041 -
Insects Apr 2022The represent a diverse group of closely related to Although they have radiated extensively in Australia, they have been the focus of few studies. Here, we...
The represent a diverse group of closely related to Although they have radiated extensively in Australia, they have been the focus of few studies. Here, we characterized the karyotypes of 12 species from several species groups and showed that they have undergone similar types of karyotypic change to those seen in . This includes heterochromatin amplification involved in length changes of the sex and 'dot' chromosomes as well as the autosomes, particularly in the group of species. Numerous weak points along the arms of the polytene chromosomes suggest the presence of internal repetitive sequence DNA, but these regions did not C-band in mitotic chromosomes, and their analysis will depend on DNA sequencing. The nucleolar organizing regions (NORs) are at the same chromosome positions in as in and the various mechanisms responsible for changing arm configurations also appear to be the same. These chromosomal studies provide a complementary resource to other investigations of this group, with several species currently being sequenced.
PubMed: 35447805
DOI: 10.3390/insects13040364 -
Comparative Cytogenetics 2022
Karyotype characteristics and gene COI sequences of Shilova et Dzhvarsheishvili, 1974 (Diptera, Chironomidae) from the South Caucasus (Republic of Georgia, Paravani river).
PubMed: 35437458
DOI: 10.3897/CompCytogen.v16.i1.79182 -
Genetics and Molecular Biology 2022Transposable elements are abundant and dynamic part of the genome, influencing organisms in different ways through their presence or mobilization, or by acting directly...
Transposable elements are abundant and dynamic part of the genome, influencing organisms in different ways through their presence or mobilization, or by acting directly on pre- and post-transcriptional regulatory regions. We compared and evaluated the presence, structure, and copy number of three hAT superfamily transposons (hobo, BuT2, and mar) in five strains of Drosophila willistoni species. These D. willistoni strains are of different geographical origins, sampled across the north-south occurrence of this species. We used sequenced clones of the hAT elements in fluorescence in-situ hybridizations in the polytene chromosomes of three strains of D. willistoni. We also analyzed the structural characteristics and number of copies of these hAT elements in the 10 currently available sequenced genomes of the willistoni group. We found that hobo, BuT2, and mar were widely distributed in D. willistoni polytene chromosomes and sequenced genomes of the willistoni group, except for mar, which is restricted to the subgroup willistoni. Furthermore, the elements hobo, BuT2, and mar have different evolutionary histories. The transposon differences among D. willistoni strains, such as variation in the number, structure, and chromosomal distribution of hAT transposons, could reflect the genomic and chromosomal plasticity of D. willistoni species in adapting to highly variable environments.
PubMed: 35297941
DOI: 10.1590/1678-4685-GMB-2021-0287 -
Chromosome Research : An International... Dec 2022Studying the probability distribution of replication initiation along a chromosome is a huge challenge. Drosophila polytene chromosomes in combination with...
Studying the probability distribution of replication initiation along a chromosome is a huge challenge. Drosophila polytene chromosomes in combination with super-resolution microscopy provide a unique opportunity for analyzing the probabilistic nature of replication initiation at the ultrastructural level. Here, we developed a method for synchronizing S-phase induction among salivary gland cells. An analysis of the replication label distribution in the first minutes of S phase and in the following hours after the induction revealed the dynamics of replication initiation. Spatial super-resolution structured illumination microscopy allowed identifying multiple discrete replication signals and to investigate the behavior of replication signals in the first minutes of the S phase at the ultrastructural level. We identified replication initiation zones where initiation occurs stochastically. These zones differ significantly in the probability of replication initiation per time unit. There are zones in which initiation occurs on most strands of the polytene chromosome in a few minutes. In other zones, the initiation on all strands takes several hours. Compact bands are free of replication initiation events, and the replication runs from outer edges to the middle, where band shapes may alter.
Topics: Animals; Drosophila; Polytene Chromosomes; Microscopy; DNA Replication; Chromosomes; Drosophila melanogaster
PubMed: 35226231
DOI: 10.1007/s10577-021-09679-w -
Nature Cell Biology Mar 2022Despite the well-established role of nuclear organization in the regulation of gene expression, little is known about the reverse: how transcription shapes the spatial...
Despite the well-established role of nuclear organization in the regulation of gene expression, little is known about the reverse: how transcription shapes the spatial organization of the genome. Owing to the small sizes of most previously studied genes and the limited resolution of microscopy, the structure and spatial arrangement of a single transcribed gene are still poorly understood. Here we study several long highly expressed genes and demonstrate that they form open-ended transcription loops with polymerases moving along the loops and carrying nascent RNAs. Transcription loops can span across micrometres, resembling lampbrush loops and polytene puffs. The extension and shape of transcription loops suggest their intrinsic stiffness, which we attribute to decoration with multiple voluminous nascent ribonucleoproteins. Our data contradict the model of transcription factories and suggest that although microscopically resolvable transcription loops are specific for long highly expressed genes, the mechanisms underlying their formation could represent a general aspect of eukaryotic transcription.
Topics: Chromosomes; Eukaryota; RNA; Ribonucleoproteins; Transcription, Genetic
PubMed: 35177821
DOI: 10.1038/s41556-022-00847-6 -
Cells Oct 2021Although heterochromatin makes up 40% of the genome, its organization remains little explored, especially in polytene chromosomes, as it is virtually not represented in...
Although heterochromatin makes up 40% of the genome, its organization remains little explored, especially in polytene chromosomes, as it is virtually not represented in them due to underreplication. Two all-new approaches were used in this work: (i) with the use of a newly synthesized line that carries three mutations, , and , suppressing the underreplication of heterochromatic regions, we obtained their fullest representation in polytene chromosomes and described their structure; (ii) 20 DNA fragments with known positions on the physical map as well as molecular genetic features of the genome (gene density, histone marks, heterochromatin proteins, origin recognition complex proteins, replication timing sites and satellite DNAs) were mapped in the newly polytenized heterochromatin using FISH and bioinformatics data. The borders of the heterochromatic regions and variations in their positions on arm 3L have been determined for the first time. The newly polytenized heterochromatic material exhibits two main types of morphology: a banding pattern (locations of genes and short satellites) and reticular chromatin (locations of large blocks of satellite DNA). The locations of the banding and reticular polytene heterochromatin was determined on the physical map.
Topics: Animals; Antibodies; Carrier Proteins; Chromosomal Proteins, Non-Histone; DNA Replication; DNA-Binding Proteins; Drosophila Proteins; Drosophila melanogaster; Genes, Essential; Genome, Insect; Guanine Nucleotide Exchange Factors; Heterochromatin; Histones; Introns; Models, Biological; Mutation; Nuclear Proteins; Polytene Chromosomes; Protein Processing, Post-Translational; Repetitive Sequences, Nucleic Acid; Replication Origin; Repressor Proteins
PubMed: 34831030
DOI: 10.3390/cells10112809 -
Open Biology Nov 2021Gap junctions mediate communication between adjacent cells and are fundamental to the development and homeostasis in multicellular organisms. In invertebrates, gap...
Gap junctions mediate communication between adjacent cells and are fundamental to the development and homeostasis in multicellular organisms. In invertebrates, gap junctions are formed by transmembrane proteins called innexins. Gap junctions allow the passage of small molecules through an intercellular channel, between a cell and another adjacent cell. The dipteran has contributed to studying the biology of invertebrates and the study of the interaction and regulation of genes during biological development. Therefore, this paper aimed to study the innexin-2 by molecular characterization, analysis of the expression profile and cellular localization. The molecular characterization results confirm that the message is from a gap junction protein and analysis of the expression and cellular localization profile shows that innexin-2 can participate in many physiological processes during the development of .
Topics: Animals; Chromosome Mapping; Computational Biology; Connexins; Gene Expression Regulation, Developmental; Insect Proteins; Models, Molecular; Nematocera; Polytene Chromosomes; Protein Conformation; Sequence Analysis, DNA; Tissue Distribution
PubMed: 34753320
DOI: 10.1098/rsob.210224 -
Journal of Genetics 2021Early genetic studies with revealed similar mutant phenotypes for many X-linked genes, in males with one and in females with two copies of the mutant allele following...
Early genetic studies with revealed similar mutant phenotypes for many X-linked genes, in males with one and in females with two copies of the mutant allele following the XY/XX mode of sex determination. These observations led to evocation of the phenomenon of dosage compensation. By the 1960s, contrasting theories were advanced by H. J. Muller and R. B. Goldschmidt to explain the equalized expression of many X-linked genes despite their dosage difference in male and female flies. Evidence from genetic studies led Muller to propose existence of many modifiers whose action on individual X-linked genes resulted, through a 'piecemeal' regulation, in equalized expression of the dosage compensated X-linked genes, while Goldschmidt believed that invocation of multiple modifiers or compensators was unnecessary since dosage compensation was a direct outcome of the sex-specific physiologies of male and female flies. Muller did not agree with some cytological studies that suggested that the single X-chromosome in male cells works twice as hard as each of the two X-chromosomes in female cells (hyperactive male X model), but preferred partial repression of each X-chromosome in female flies. This historical perspective relates these divergent theories with my own doctoral work in A. S. Mukherjee's laboratory at Calcutta University, which, while ruling out Golschmidt's sex-physiology theory, established cell-autonomous regulation of the earlier proposed hyperactivity of the single X in male in a piecemeal manner.
Topics: Animals; Chromosomes, Insect; Dosage Compensation, Genetic; Drosophila; Female; Genes, X-Linked; Genetics; History, 20th Century; India; Male; Models, Genetic; Polytene Chromosomes; X Chromosome
PubMed: 34622796
DOI: No ID Found -
Scientific Reports Oct 2021The inverse dosage effect caused by chromosome number variations shows global consequences in genomic imbalance including sexual dimorphism and an X chromosome-specific...
The inverse dosage effect caused by chromosome number variations shows global consequences in genomic imbalance including sexual dimorphism and an X chromosome-specific response. To investigate the relationship of the MSL complex to genomic imbalance, we over-expressed MSL2 in autosomal and sex chromosomal aneuploids, and analyzed the different transcriptomes. Some candidate genes involved in regulatory mechanisms have also been tested during embryogenesis using TSA-FISH. Here we show that the de novo MSL complex assembled on the X chromosomes in females further reduced the global expression level on the basis of 2/3 down-regulation caused by the inverse dosage effect in trisomy through epigenetic modulations rather than induced dosage compensation. Plus, the sexual dimorphism effect in unbalanced genomes was further examined due to the pre-existing of the MSL complex in males. All these results demonstrate the dynamic functions of the MSL complex on global gene expression in different aneuploid genomes.
Topics: Aneuploidy; Animals; Computational Biology; DNA-Binding Proteins; Drosophila; Drosophila Proteins; Ectopic Gene Expression; Female; Gene Expression Profiling; Gene Expression Regulation; Gene Regulatory Networks; Male; Multiprotein Complexes; Polytene Chromosomes; Sex Characteristics; Transcription Factors; X Chromosome
PubMed: 34608252
DOI: 10.1038/s41598-021-99268-y