Transcriptomic analysis of meiotic genes during the mitosis-to-meiosis transition in Drosophila females.

Germline cells produce gametes, which are specialized cells essential for sexual reproduction. Germline cells first amplify through several rounds of mitosis before switching to the meiotic program, which requires specific sets of proteins for DNA recombination, chromosome pairing, and segregation. Surprisingly, we previously found that some proteins of the synaptonemal complex, a prophase I meiotic structure, are already expressed and required in the mitotic region of Drosophila females.

Premeiotic pairing of homologous chromosomes during male meiosis.

In the early stages of meiosis, maternal and paternal chromosomes pair with their homologous partner and recombine to ensure exchange of genetic information and proper segregation. These events can vary drastically between species and between males and females of the same species. In in contrast to females, males do not form synaptonemal complexes (SCs), do not recombine, and have no crossing over; yet, males are able to segregate their chromosomes properly.

tRNA processing defects induce replication stress and Chk2-dependent disruption of piRNA transcription.

RNase P is a conserved endonuclease that processes the 5' trailer of tRNA precursors. We have isolated mutations in Rpp30, a subunit of RNase P, and find that these induce complete sterility in Drosophila females. Here, we show that sterility is not due to a shortage of mature tRNAs, but that atrophied ovaries result from the activation of several DNA damage checkpoint proteins, including p53, Claspin, and Chk2.

Live cell imaging in Drosophila melanogaster.

Although many of the techniques of live cell imaging in Drosophila melanogaster are also used by the greater community of cell biologists working on other model systems, studying living fly tissues presents unique difficulties with regard to keeping the cells alive, introducing fluorescent probes, and imaging through thick, hazy cytoplasm. This article outlines the major tissue types amenable to study by time-lapse cinematography and different methods for keeping the cells alive. It describes various imaging and associated techniques best suited to following changes in the distribution of fluorescently labeled molecules in real time in these tissues.

Drosophila larval fillet preparation and imaging of neurons.

Drosophila is an established system in which to study synaptic development, function, and plasticity. A particular advantage of the larval neuromuscular system is its consistent well-defined segmental arrangement of neurons and muscle targets. Indeed, the motor neurons of the Drosophila central nervous system are particularly well characterized in terms of origin, identity, morphology, and electrophysiology, and have been used for studies on axonal transport of organelles, vesicle trafficking, and recycling.

Drosophila macrophage preparation and screening.

Drosophila plasmatocytes, also known as macrophages, are part of the Drosophila innate immune system and also have roles during development. In late-stage embryos, it is possible to image macrophage migration in situ during development and when they converge at sites of wounding. This protocol describes the isolation of macrophages from third instar Drosophila larvae.

Collection and mounting of Drosophila embryos for imaging.

The fruit fly Drosophila melanogaster is an important model for basic research into the molecular mechanisms underlying cell function and development, as well as a major biomedical research tool. A significant advantage of Drosophila is the ability to apply live cell imaging to a variety of living tissues that can be dissected and imaged in vivo, ex vivo, or in vitro. For example, such imaging can be used for visual genetic screens such as analysis of morphological characteristics or of the distribution of fluorescently tagged proteins in living embryos.

Isolation of Drosophila egg chambers for imaging.

The fruit fly Drosophila melanogaster is an important model for basic research into the molecular mechanisms underlying cell function and development, as well as a major biomedical research tool. A significant advantage of Drosophila is the ability to apply live cell imaging to a variety of living tissues that can be dissected and imaged in vivo, ex vivo, or in vitro. Drosophila egg chambers, for example, have proven to be a useful model system for studying border cell migration, Golgi unit transport, the rapid movement of mRNA and protein particles, and the role of microtubules in meiosis and oocyte differentiation.

[Development hip dysplasia. Knowledge in pediatricians].

Introduction: The diagnosis of developmental hip dysplasia (DHD) is based on clinical evaluation of newborns. Early conservative orthopaedic management usually resolves the problem, but delay of proper recognition and treatment can cause poorer prognosis and severe consequences.

Objectives: To evaluate the paediatrician's theoretical knowledge level in DHD in the city of Tijuana, Mexico.

Serine phosphorylation regulates paxillin turnover during cell migration.

Background: Paxillin acts as an adaptor protein that localizes to focal adhesion. This protein is regulated during cell migration by phosphorylation on tyrosine, serine and threonine residues. Most of these phosphorylations have been implicated in the regulation of different steps of cell migration.