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PubMed2025

Recently Evolved, Stage-Specific Genes Are Enriched at Life-Stage Transitions in Flies.

Understanding how genomic information is selectively utilized across different life stages is essential for deciphering the developmental and evolutionary strategies of metazoans. In holometabolous insects, the dynamic expression of genes enables distinct functional adaptations at embryonic, larval, pupal, and adult stages, likely contributing to their evolutionary success. While Drosophila melanogaster (D. melanogaster) has been extensively studied, less is known about the evolutionary dynamics that could govern stage-specific gene expression. To address this question, we compared the distribution of stage-specific genes, that is, genes expressed in temporally restricted developmental stages, across the development of D. melanogaster and Aedes aegypti (A. aegypti). Using tau-scoring, a computational method to determine gene expression specificity, we found that, on average, a large proportion of genes (20%-30% of all protein-coding genes) in both species exhibit restricted expression to specific developmental stages. Phylostratigraphy analysis, a method to date the age of genes, further revealed that stage-specific genes fall into two major categories: highly conserved and recently evolved. Notably, many of the recently evolved and stage-specific genes identified in A. aegypti and D. melanogaster are restricted to Diptera order (20%-35% of all stage-specific genes), highlighting ongoing evolutionary processes that continue to shape life-stage transitions. Overall, our findings underscore the complex interplay between gene evolutionary age, expression specificity, and morphological transformations in development. These results suggest that the attraction of genes to critical life-stage transitions is an ongoing process that may not be constant across evolutionary time or uniform between different lineages, offering new insights into the adaptability and diversification of dipteran genomes.

Animals↗
PubMed2004

Regulation of cytoskeletal dynamics by actin-monomer-binding proteins.

The actin cytoskeleton is a vital component of several key cellular and developmental processes in eukaryotes. Many proteins that interact with filamentous and/or monomeric actin regulate the structure and dynamics of the actin cytoskeleton. Actin-filament-binding proteins control the nucleation, assembly, disassembly and crosslinking of actin filaments, whereas actin-monomer-binding proteins regulate the size, localization and dynamics of the large pool of unpolymerized actin in cells. In this article, we focus on recent advances in understanding how the six evolutionarily conserved actin-monomer-binding proteins - profilin, ADF/cofilin, twinfilin, Srv2/CAP, WASP/WAVE and verprolin/WIP - interact with actin monomers and regulate their incorporation into filament ends. We also present a model of how, together, these ubiquitous actin-monomer-binding proteins contribute to cytoskeletal dynamics and actin-dependent cellular processes.

Actins↗
PubMed2025

Asymmetric development and function of paired sperm-storage organs in Drosophila melanogaster.

Paired structures often have similar forms and functions, but the processes underlying their formation can differ. They may originate from a common source or from parallel sources, or arise from distinct precursors that follow separate developmental pathways, ultimately converging on comparable structures and roles. When asymmetries emerge and persist through development, members of the pair can specialize in ways that might increase fitness. Here, we report that the Drosophila melanogaster female's pair of spermathecae, which appear similar and have the common role of sperm storage, derive from different developmental compartments defined by expression of lineage-tracing markers corresponding, respectively, to the key patterning genes engrailed and wingless. We further find that the two spermathecae show significant differences in size, secretory activity, and calcium levels and, perhaps as a consequence, sperm retention dynamics. These results open broad avenues for understanding how developmental, physiological, and behavioral asymmetries arise and impact reproductive success.

Animals↗
PubMed2004

Spectral analysis of the sleep electroencephalogram during adolescence.

OBJECTIVES: To describe developmental changes of the human sleep electroencephalogram (EEG) during adolescence using EEG spectral analysis and specifically to compare the nocturnal dynamics of slow-wave activity (EEG spectral power 0.6-4.6 Hz, a marker for sleep homeostatic pressure) in prepubertal and mature adolescents. DESIGN: After 10 nights on a fixed 10-hour sleep schedule without daytime naps, participants were studied during a 10-hour baseline night. SETTING: Data were collected in a 4-bed sleep research laboratory. PARTICIPANTS: Eight prepubertal children (pubertal stage Tanner 1; mean age 11.3 years, SD +/- 1.2, 4 boys) and 8 mature adolescents (Tanner 5; mean age 14.1 years, +/- 1.3, 3 boys). INTERVENTIONS: Not applicable. MEASUREMENTS: All-night polysomnography was performed. Sleep stages were scored according to conventional criteria. EEG power spectra (of derivation C3/A2) were calculated using a fast Fourier transform routine. RESULTS: A reduction of non-rapid eye movement (NREM) sleep stage 4 (by 40.1%) and greater amounts of stage 2 sleep (19.7%) were found in mature compared to prepubertal adolescents. NREM sleep EEG power was lower in the frequency ranges < 7 Hz, 11.8 to 12.6 Hz, and 16.2 to 16.8 Hz in mature adolescents. A reduction of rapid eye movement sleep spectral power was present in the frequency ranges < 8.6 Hz and 9.6 to 15 Hz for mature compared to prepubertal adolescents. Slow-wave activity showed identical dynamics within individual NREM sleep episodes and across the night in both developmental groups. CONCLUSIONS: The homeostatic recuperative drive during sleep remains unchanged across puberty. The decline of slow-wave sleep during adolescence may reflect developmental changes of the brain rather than changes of sleep regulatory processes.

Adolescent↗
PubMed1991

Implications of a dynamical systems approach to understanding infant kicking behavior.

Implications of the dynamical systems approach to understanding movement dysfunction in infants are discussed. Traditional theories of motor development attribute changes in movement to the hierarchical maturation of the central nervous system. The dynamical systems approach emphasizes that movement self-organizes as the result of the interaction of the participating subsystems in developmental and real time. In this article, I discuss, from the theoretical perspective of the dynamical systems approach, the organization of leg movements in low- and high-risk preterm and full-term infants, developmental changes in movement in low-risk preterm infants from 34 weeks' gestational age to 40 weeks' postgestational age, and differences in movement between low-risk preterm infants at 40 weeks' postgestational age and full-term infants. Preliminary data on high-risk preterm infants are presented. Based on these data, the necessity to review and reinterpret traditional concepts of motor development is explored. Suggestions are offered and questions posed on how the dynamical systems perspective may influence the practice of physical therapy in the evaluation, and treatment of infants at risk for movement dysfunction.

Gestational Age↗
PubMed1993

Development of larval muscle properties in the embryonic myotubes of Drosophila melanogaster.

The entire developmental history of muscle membrane electrogenesis can be observed in the embryonic myotubes of Drosophila. We have examined the development of ionic currents and muscle properties using whole-cell patch-clamp techniques throughout embryonic myogenesis. In the early stages of myogenesis, from myoblast fusion through to establishing epidermal insertions, the myotubes are electrically inert and are electrically and dye coupled to adjacent myotubes. Membrane electrogenesis begins in the mid-embryonic stages (early stage 16), when the myotubes abruptly uncouple, revealing the first of five prominent extrajunctional currents: a small, inward, voltage-gated calcium current (ICa). The uncoupling of the embryonic myotubes heralds the onset of extremely rapid electrogenesis; within several minutes both the fast, inactivating (IA; Shaker) and delayed, noninactivating (IK) outward potassium currents, the stretch-activated outward potassium current, and the junctional glutamate-gated inward current all appear and begin to develop in a current-specific manner. Very late in embryogenesis (late stage 17), the calcium-dependent, outward potassium currents [rapid, inactivating (ICF; slowpoke) then delayed, noninactivating (ICS)] develop, completing the complement of macroscopic currents in the mature larval muscle. Hence, the voltage-gated currents (ICa, IA, and IK, respectively) appear relatively early, and the calcium-dependent currents (ICF, ICS) appear only very late during myogenesis. This developmental progression of current maturation is reflected in dynamic changes in the voltage responses of the embryonic membrane, from wholly passive response to current injection in the early, coupled myotubes to regenerating, overshooting action potentials in the mature embryonic muscle. The earliest embryonic IA current has a midpoint of inactivation 40 mV more negative than the IA current in the mature embryo. As myogenesis proceeds, the inactivation curve develops a biphasic character, suggesting that a low-inactivation IA channel is present in early development and progressively replaced by the mature form as development proceeds. The current at all stages can be completely eliminated in Shaker mutants (ShKS133). These findings suggest that an embryonic form of the Shaker IA channel is present during early myogenesis. The prominent IA current present in early development is almost entirely inactivated at the physiological resting potential; the significance and mechanism of this developmental shift are unclear.

Animals↗
PubMed2006

Identification and developmental expression of the ets gene family in the sea urchin (Strongylocentrotus purpuratus).

A systematic search in the available scaffolds of the Strongylocentrotus purpuratus genome has revealed that this sea urchin has 11 members of the ets gene family. A phylogenetic analysis of these genes showed that almost all vertebrate ets subfamilies, with the exception of one, so far found only in mammals, are each represented by one orthologous sea urchin gene. The temporal and spatial expression of the identified ETS factors was also analyzed during embryogenesis. Five ets genes (Sp-Ets1/2, Sp-Tel, Sp-Pea, Sp-Ets4, Sp-Erf) are also maternally expressed. Three genes (Sp-Elk, Sp-Elf, Sp-Erf) are ubiquitously expressed during embryogenesis, while two others (Sp-Gabp, Sp-Pu.1) are not transcribed until late larval stages. Remarkably, five of the nine sea urchin ets genes expressed during embryogenesis are exclusively (Sp-Ets1/2, Sp-Erg, Sp-Ese) or additionally (Sp-Tel, Sp-Pea) expressed in mesenchyme cells and/or their progenitors. Functional analysis of Sp-Ets1/2 has previously demonstrated an essential role of this gene in the specification of the skeletogenic mesenchyme lineage. The dynamic, and in some cases overlapping and/or unique, developmental expression pattern of the latter five genes suggests a complex, non-redundant function for ETS factors in sea urchin mesenchyme formation and differentiation.

Animals↗
PubMed1995

The implications of age of onset for delinquency risk. II: Longitudinal data.

The role of age of onset in the level of involvement in delinquent behavior as marked by seriousness and chronicity of involvement continues to draw extensive attention from researchers. This issue bears on some of the key causal contentions about the dynamism of involvement and the validity of a developmental model of antisocial behavior risk. Five waves of the National Youth Survey were utilized here to determine if, among a nationally representative sample, there was evidence of onset age influence on later involvement. Results suggest that early onset (before age 12) relates to higher rates of more serious acts over a longer period of time for boys and girls. Overall, the results suggest support for early onset spurring on later involvement, but the contribution is small once psychosocial predictors are considered. Onset age seems most important in understanding involvement in serious crime over several years. Involvement is explained best by peer variables for males and school and family variables for females. Onset age is explained by a wider range of variables than involvement and there is greater similarity of the psychosocial variables that explain onset for both genders. The interaction of involvement and predictors was noted, suggesting a dynamic model of risk. Implications for prediction and prevention are discussed.

Adolescent↗
PubMed2025

Genome-wide identification and expression profiling of the MADS-box gene family in Lavandula angustifolia.

BACKGROUND: MADS-box&#xa0;genes encode transcription factors critical for plant development, particularly floral organogenesis, flowering time regulation, and adaptation to environmental stresses. Among these, the MIKCC-type genes are pivotal regulators in floral developmental processes. Although the evolutionary diversification and functional dynamics of MADS-box genes have been extensively characterized in model plants such as Arabidopsis thaliana and Oryza sativa, their evolutionary relationships and functional profiles in Lavandula angustifolia, an economically significant aromatic plant, remain poorly understood. RESULTS: Genome-wide analysis identified 173 MADS-box genes in L. angustifolia, categorized into type I (M&#x3b1;: 26; M&#x3b2;: 0; M&#x3b3;: 10) and type II (MIKCC: 125; MIKC*: 12) based on phylogenetic comparisons with A. thaliana. The MIKCC subgroup was further subdivided into 12 subclasses, including genes central to the ABCDE model of floral organ specification. Structural analyses revealed distinct conserved motifs and exon-intron configurations specific to each subgroup, indicative of functional divergence. Synteny analysis demonstrated Whole Genome Duplication (WGD) and segmental duplications as major contributors to MIKCC gene family expansion, notably among genes linked to floral organ development. Expression profiling via RNA-seq and quantitative real-time PCR (qPCR) showed type II MADS-box genes exhibited higher expression levels with pronounced tissue-specific and developmental stage-specific expression patterns compared to type I genes. Many type II genes displayed significant associations with floral organogenesis, floral transition, and abiotic stress responses, underscoring their essential roles in reproductive development and environmental adaptability in L. angustifolia. CONCLUSIONS: The identification and comprehensive characterization of 173 MADS-box genes in L. angustifolia highlight the significant expansion of the MIKCC subgroup driven primarily by WGD and segmental duplications. The distinct structural features and specific expression patterns observed provide insights into the functional divergence and complexity of these genes, particularly regarding floral organogenesis and adaptation to environmental stress. This study establishes a robust molecular basis for further functional analysis and genetic improvement of aromatic plants.

MADS Domain Proteins↗
PubMed2004

Developmental switch in axon guidance modes of hippocampal mossy fibers in vitro.

Hippocampal mossy fibers (MFs), axons of dentate granule cells, run through a narrow strip, called the stratum lucidum, and make synaptic contacts with CA3 pyramidal cells. This stereotyped pathfinding is assumed to require a tightly controlled guidance system, but the responsible mechanisms have not been proven directly. To clarify the cellular basis for the MF pathfinding, microslices of the dentate gyrus (DG) and Ammon's horn (AH) were topographically arranged in an organotypic explant coculture system. When collagen gels were interposed between DG and AH slices prepared from postnatal day 6 (P6) rats, the MFs passed across this intervening gap and reached CA3 stratum lucidum. Even when the recipient AH was chemically pre-fixed with paraformaldehyde, the axons were still capable of accessing their normal target area only if the DG and AH slices were directly juxtaposed without a collagen bridge. The data imply that diffusible and contact cues are both involved in MF guidance. To determine how these different cues contribute to MF pathfinding during development, a P6 DG slice was apposed simultaneously to two AH slices prepared from P0 and P13 rats. MFs projected normally to both the host slices, whereas they rarely invaded P0 AH when the two hosts were fixed. Early in development, therefore, the MFs are guided mainly by a chemoattractant gradient, and thereafter, they can find their trajectories by a contact factor, probably via fasciculation with pre-established MFs. The present study proposes a dynamic paradigm in CNS axon pathfinding, that is, developmental changes in axon guidance cues.

Animals↗
PubMed2003

Tau phosphorylation by cyclin-dependent kinase 5/p39 during brain development reduces its affinity for microtubules.

The microtubule-associated protein tau is a developmentally regulated neuronal phosphoprotein. The phosphorylation of tau reduces its ability to bind and stabilize axonal microtubules during axonal growth. Although tau is phosphorylated by cyclin-dependent kinase 5 (Cdk5) in vitro, its in vivo roles remain unclear. Here, we show that tau is phosphorylated by Cdk5/p39 during brain development, resulting in a reduction of its affinity for microtubules. The activity of Cdk5 is tightly regulated by association with its neuronal activators, p35 or p39. The p35 and p39 expression levels were investigated in the developing mouse brain; the p39 expression level was higher in embryonic hind brain and spinal cord and in postnatal cerebral cortex, whereas that of p35 was most prominent in cerebral cortex at earlier stages of development. The ability of Cdk5 to phosphorylate tau was higher when in association with p39 than in association with p35. Tau phosphorylation at Ser-202 and Thr-205 was decreased in Cdk5-/- mouse brain but not in p35-/- mouse brain, suggesting that Cdk5/p39 is responsible for the in vivo phosphorylation of tau at these sites. Our data suggest that tau phosphorylation by Cdk5 may provide the neuronal microtubules with dynamic properties in a region-specific and developmentally regulated manner.

Animals↗
PubMed1987

Dynamics of behaviour during neuronal morphogenesis in culture.

We report a developmental sequence in the type and frequency of behaviours of neurons differentiating in vitro. We characterised these changes with extensive analysis of time-lapse sequences from both the continuing cell line pheochromocytoma PC12 and primary mixed cell culture of cat and mouse central nervous system. PC12 cells activated by nerve growth factor (NGF) differentiate in a uniform and synchronous manner. This allowed the first quantification of changes in different neuron behaviours during morphogenesis. Shortly after NGF activation, PC12 cells are highly labile in morphology and exhibit a large variety of morphological behaviours. During the first week of differentiation, the frequency of these behaviours declines, and gross morphology becomes more stable. The frequency of neurite initiation after 1 week in NGF is one-seventh what it was after 2 days in NGF. Over the same period, neurite retraction declines to one-third, and somal migration ceases altogether. Growth-cone activity does not decline during development. These behaviour changes correlate with published data on the differentiation of the neurite cytoskeleton. A qualitatively similar ontogeny was noted in the differentiation of CNS neurons in mixed cell culture. Major differences occur in the relative timing of changes in behaviours. Mature, stable morphology is not detected in these cultures until 7 weeks in vitro.

Adrenal Gland Neoplasms↗
PubMed1998

Binding of trithorax and Polycomb proteins to the bithorax complex: dynamic changes during early Drosophila embryogenesis.

In Drosophila, the maintenance of developmentally important transcription patterns is controlled at the level of chromatin structure. The Polycomb group (PcG) and trithorax group (trxG) genes encode proteins involved in chromatin remodelling. PcG genes have been proposed to act by packaging transcriptional repressed chromosomal domains into condensed heterochromatin-like structures. Some of the trxG proteins characterized so far are members of chromatin opening complexes (e.g. SWI/SNF and GAGA/NURF) which facilitate binding of transcription factors and components of the basal transcriptional machinery. Genetic and biochemical data suggest that these two groups of regulatory factors may act through a common set of DNA elements. In the present study, we have investigated the binding of Trithorax (TRX) and Polycomb (PC) protein in the bithorax complex (BX-C) during embryogenesis. In addition, we have identified the minimal fragments from the Ultrabithorax (Ubx) regulatory region that are capable of recruiting TRX to chromosomal sites containing them. Comparative analysis of the binding of the two proteins shows that TRX and PC bind target sequences (PcG-regulated elements, PREs) by cellular blastoderm, when BX-C transcription begins. At the same stage, TRX but not PC is strongly associated with core promoters. Later, at germ band extension, the time of derepression in Polycomb mutants, PC binding is also detected outside core PREs and additionally binds to the fragments containing promoters.

Animals↗
PubMed1981

[Interactions between vessel wall and blood and their role in developmental and therapy of arterial perfusion disorders (author's transl)].

The dynamic balance between the vessel wall and the systems of the platelets, of coagulation and of the fibrinolysis, termed vessel wall-blood homoiostasis, can be altered in a physiologically suitable way as well as pathologically. A disturbance of the vessel wall-blood homoiostasis is considered the key process of the pathogenesis of all obliterating angiopathies. This view can explain why different risk factors may lead to the same picture of obliterative arteriosclerosis. From this point of view practical consequences for the treatment arise which may - under most favorable circumstances - render a restitution and integrum possible or at least a regression of obliterative processes.

Arteriosclerosis↗
PubMed2003

Imaging mitochondrial organization in living primate oocytes and embryos using multiphoton microscopy.

We employed multiphoton laser scanning microscopy (MPLSM) to image changes in mitochondrial distribution in living rhesus monkey embryos. This method of imaging does not impair development; thus, the same specimen can be visualized multiple times at various developmental stages. Not only does this increase the amount of information that can be gathered on a single specimen but it permits the correlation of early events with subsequent development in the same specimen. Here we demonstrate the utility of MPLSM for determining changes in mitochondrial organization at various developmental stages and show that rhesus zygotes possess a distinct accumulation of mitochondria between the pronuclei prior to syngamy. We present evidence that suggests that this pronuclear accumulation may be positively correlated with development to the blastocyst stage-in the same embryo-thereby illustrating how MPLSM can be used to correlate cellular dynamics of primate oocytes and early embryos with their developmental potential. Understanding the relationship between mitochondrial distribution and the subsequent development of mammalian embryos, particularly primates, will increase our ability to improve embryo culture technologies, including those used for human assisted reproduction.

Animals↗
PubMed2001

DrhoGEF3 encodes a new Drosophila DH domain protein that exhibits a highly dynamic embryonic expression pattern.

The Rho GTPases regulate many different cellular and developmental processes, and activation of Rho GTPase signalling is mediated through interaction with the Dbl homology (DH) protein domain. We describe the expression pattern of DrhoGEF3 (cytological position 61B1-B3), which encodes a new member of the DH domain protein family from Drosophila and is a homologue of the human protein hPEM-2. During gastrulation and germ band extension, DrhoGEF3 exhibits a segmented expression pattern. DrhoGEF3 is subsequently expressed in the visceral mesoderm, at the sites of muscle attachment and in specific groups of sub-epidermal cells. The possible function of such a dynamically expressed signalling molecule is discussed.

Amino Acid Sequence↗
PubMed1994

Infant hip sonography: current concepts.

Sonography of the infant hip has gained wide acceptance in the decade since its introduction. The two principle techniques of Graf and Harcke have been combined with the proposal of a Dynamic Standard Minimum Examination. Whereas sonography is used increasingly to manage developmental dislocation and/or displasia of the hip, there is no agreement on the use of sonography for universal newborn screening. This article describes in detail the Dynamic Standard Minimum Sonographic Examination of the infant hip. In addition, this article reviews the classification and management of infant hip disorders.

Hip Dislocation↗