Epigenetic inheritance and gene expression regulation in early Drosophila embryos.

Precise spatiotemporal regulation of gene expression is of paramount importance for eukaryotic development. The maternal-to-zygotic transition (MZT) during early embryogenesis in Drosophila involves the gradual replacement of maternally contributed mRNAs and proteins by zygotic gene products. The zygotic genome is transcriptionally activated during the first 3 hours of development, in a process known as "zygotic genome activation" (ZGA), by the orchestrated activities of a few pioneer factors.

Knockdown of Sec16 causes early lethality and defective deposition of the protein Rp30 in the eggshell of the vector .

In nearly every species of insect, embryonic development takes place outside of the mother's body and is entirely dependent on the elements that the mother had previously stored within the eggs. It is well known that the follicle cells (FCs) synthesize the eggshell (chorion) components during the process of choriogenesis, the final step of oogenesis before fertilization. These cells have developed a specialization in the massive production of chorion proteins, which are essential for the protection and survival of the embryo.

External beam radiation therapy for recurrent or residual thyroid cancer: What is the best treatment time and the best candidate for long-term local disease control?

Introduction: Cervical disease control might be challenging in advanced thyroid cancer (DTC). Indications for cervical external beam radiation therapy (EBRT) are controversial.

Purpose: To identify clinical and molecular factors associated with control of cervical disease with EBRT.

Gene identification and RNAi-silencing of p62/SQSTM1 in the vector Rhodnius prolixus reveals a high degree of sequence conservation but no apparent deficiency-related phenotypes in vitellogenic females.

Autophagy and the ubiquitin-proteasome system (UPS) are important cellular mechanisms that coordinate protein degradation essential for proteostasis. P62/SQSTM1 is a receptor cargo protein able to deliver ubiquitinated targets to the proteasome proteolytic complex and/or to the autophagosome. In the insect vector of Chagas disease, Rhodnius prolixus, previous works have shown that the knockdown of different autophagy-related genes (ATGs) and ubiquitin-conjugating enzymes resulted in abnormal oogenesis phenotypes and embryo lethality.

Atypical strategies for cuticle pigmentation in the blood-feeding hemipteran Rhodnius prolixus.

Pigmentation in insects has been linked to mate selection and predator evasion, thus representing an important aspect for natural selection. Insect body color is classically associated to the activity of tyrosine pathway enzymes, and eye color to pigment synthesis through the tryptophan and guanine pathways, and their transport by ATP-binding cassette proteins. Among the hemiptera, the genetic basis for pigmentation in kissing bugs such as Rhodnius prolixus, that transmit Chagas disease to humans, has not been addressed.

The genotypic and phenotypic impact of hypoxia microenvironment on glioblastoma cell lines.

Background: Glioblastoma is a fatal brain tumour with a poor patient survival outcome. Hypoxia has been shown to reprogram cells towards a stem cell phenotype associated with self-renewal and drug resistance properties. Activation of hypoxia-inducible factors (HIFs) helps in cellular adaptation mechanisms under hypoxia.

Transovarial transmission of a core virome in the Chagas disease vector Rhodnius prolixus.

Triatomine assassin bugs comprise hematophagous insect vectors of Trypanosoma cruzi, the causative agent of Chagas disease. Although the microbiome of these species has been investigated to some extent, only one virus infecting Triatoma infestans has been identified to date. Here, we describe for the first time seven (+) single-strand RNA viruses (RpV1-7) infecting Rhodnius prolixus, a primary vector of Chagas disease in Central and South America.

Gene expression profiling of Trypanosoma cruzi in the presence of heme points to glycosomal metabolic adaptation of epimastigotes inside the vector.

Chagas disease, also known as American trypanosomiasis, is a potentially life-threatening illness caused by the protozoan parasite, Trypanosoma cruzi, and is transmitted by triatomine insects during its blood meal. Proliferative epimastigotes forms thrive inside the insects in the presence of heme (iron protoporphyrin IX), an abundant product of blood digestion, however little is known about the metabolic outcome of this signaling molecule in the parasite. Trypanosomatids exhibit unusual gene transcription employing a polycistronic transcription mechanism through trans-splicing that regulates its life cycle.

Transcriptomic and functional analyses of the piRNA pathway in the Chagas disease vector Rhodnius prolixus.

The piRNA pathway is a surveillance system that guarantees oogenesis and adult fertility in a range of animal species. The pathway is centered on PIWI clade Argonaute proteins and the associated small non-coding RNAs termed piRNAs. In this study, we set to investigate the evolutionary conservation of the piRNA pathway in the hemimetabolous insect Rhodnius prolixus.

Comparative Genomics in Drosophila.

Since the pioneering studies of Thomas Hunt Morgan and coworkers at the dawn of the twentieth century, Drosophila melanogaster and its sister species have tremendously contributed to unveil the rules underlying animal genetics, development, behavior, evolution, and human disease. Recent advances in DNA sequencing technologies launched Drosophila into the post-genomic era and paved the way for unprecedented comparative genomics investigations. The complete sequencing and systematic comparison of the genomes from 12 Drosophila species represents a milestone achievement in modern biology, which allowed a plethora of different studies ranging from the annotation of known and novel genomic features to the evolution of chromosomes and, ultimately, of entire genomes.

Rhodnius prolixus: From classical physiology to modern developmental biology.

The hemiptera Rhodnius prolixus is a blood-feeding insect and a primary vector of Trypanosoma cruzi, the etiological agent of the Chagas disease. Over the past century, Rhodnius has been the subject of intense investigations, which have contributed to unveil important aspects of metabolism and physiology in insects. Recent technological innovations are helping dissect the genetic and molecular underpinnings of Rhodnius embryogenesis and organogenesis, thus fostering the use of this important species in the fields of developmental and evolutionary biology.

Integrative analysis unveils new functions for the Cutoff protein in noncoding RNA biogenesis and gene regulation.

Piwi-interacting RNAs (piRNAs) are central components of the piRNA pathway, which directs transposon silencing and guarantees genome integrity in the germ cells of several metazoans. In , piRNAs are produced from discrete regions of the genome termed piRNA clusters, whose expression relies on the RDC complex comprised of the core proteins Rhino, Deadlock, and Cutoff. To date, the RDC complex has been exclusively implicated in the regulation of the piRNA loci.

Mapping the pericentric heterochromatin by comparative genomic hybridization analysis and chromosome deletions in Drosophila melanogaster.

Heterochromatin represents a significant portion of eukaryotic genomes and has essential structural and regulatory functions. Its molecular organization is largely unknown due to difficulties in sequencing through and assembling repetitive sequences enriched in the heterochromatin. Here we developed a novel strategy using chromosomal rearrangements and embryonic phenotypes to position unmapped Drosophila melanogaster heterochromatic sequence to specific chromosomal regions.

The Cutoff protein regulates piRNA cluster expression and piRNA production in the Drosophila germline.

In a broad range of organisms, Piwi-interacting RNAs (piRNAs) have emerged as core components of a surveillance system that protects the genome by silencing transposable and repetitive elements. A vast proportion of piRNAs is produced from discrete genomic loci, termed piRNA clusters, which are generally embedded in heterochromatic regions. The molecular mechanisms and the factors that govern their expression are largely unknown.

miR-184 has multiple roles in Drosophila female germline development.

Posttranscriptional regulation plays a crucial role in germline and early embryonic development, but the underlying mechanisms are only partially understood. Here we report the genetic and molecular analysis of the maternally and zygotically expressed microRNA miR-184 in Drosophila. Loss of miR-184 leads to multiple severe defects during oogenesis and early embryogenesis, culminating in the complete loss of egg production.

Masculinization of XX Drosophila transgenic flies expressing the Ceratitis capitata DoublesexM isoform.

The Doublesex (DSX) transcription factor regulates somatic sexual differentiation in Drosophila melanogaster. Female and male isoforms (DSXF and DSXM) are produced due to sex-specific RNA splicing. Here we show that in the distantly related dipteran Ceratitis capitata, the DSXM male-specific isoform is conserved and able to induce masculinization of both somatic and germline tissues when ectopically expressed in XX Drosophila transgenic individuals.

zucchini and squash encode two putative nucleases required for rasiRNA production in the Drosophila germline.

RNAi is a widespread mechanism by which organisms regulate gene expression and defend their genomes against viruses and transposable elements. Here we report the identification of Drosophila zucchini (zuc) and squash (squ), which function in germline RNAi processes. Zuc and Squ contain domains with homologies to nucleases.

Cutoff and aubergine mutations result in retrotransposon upregulation and checkpoint activation in Drosophila.

Gametogenesis is a highly regulated process in all organisms. In Drosophila, a meiotic checkpoint which monitors double-stranded DNA breaks and involves Drosophila ATR and Chk2 coordinates the meiotic cell cycle with signaling events that establish the axis of the egg and embryo. Checkpoint activity regulates translation of the transforming growth-factor-alpha-like Gurken signaling molecule which induces dorsal cell fates in the follicle cells [1-3].

Evolutionary conservation of Ceratitis capitata transformer gene function.

Transformer functions as a binary switch gene in the sex determination and sexual differentiation of Drosophila melanogaster and Ceratitis capitata, two insect species that separated nearly 100 million years ago. The TRA protein is required for female differentiation of XX individuals, while XY individuals express smaller, presumably nonfunctional TRA peptides and consequently develop into adult males. In both species, tra confers female sexual identity through a well-conserved double-sex gene.

The transformer gene in Ceratitis capitata provides a genetic basis for selecting and remembering the sexual fate.

The medfly Ceratitis capitata contains a gene (Cctra) with structural and functional homology to the Drosophila melanogaster sex-determining gene transformer (tra). Similar to tra in Drosophila, Cctra is regulated by alternative splicing such that only females can encode a full-length protein. In contrast to Drosophila, however, where tra is a subordinate target of Sex-lethal (Sxl), Cctra seems to initiate an autoregulatory mechanism in XX embryos that provides continuous tra female-specific function and act as a cellular memory maintaining the female pathway.