Linear podosomes display low Cdc42 activity for proplatelet elongation by megakaryocytes.

Blood platelets result from differentiation of megakaryocytes (MKs) into the bone marrow. It culminates with the extension of proplatelets (PPT) through medullar sinusoids and release of platelets in the blood stream. Those processes are regulated by contact with the microenvironment mediated by podosomes.

Protocol to locally express cxcl12a during zebrafish olfactory organ development by combining IR-LEGO with live imaging.

Temporal and spatial regulation of gene expression is crucial for proper embryonic development. Infrared laser-evoked gene operator (IR-LEGO) can provide information for various developmental processes. Here, we present a protocol to locally express cxcl12a during zebrafish olfactory organ development using a combination of IR-LEGO and live imaging.

Mapping of the amniotic fluid proteome of fetuses with congenital anomalies of the kidney and urinary tract identifies plastin 3 as a protein involved in glomerular integrity.

Congenital anomalies of the kidney and the urinary tract (CAKUT) are the first cause of chronic kidney disease in childhood. Several genetic and environmental origins are associated with CAKUT, but most pathogenic pathways remain elusive. Considering the amniotic fluid (AF) composition as a proxy for fetal kidney development, we analyzed the AF proteome from non-severe CAKUT (n = 19), severe CAKUT (n = 14), and healthy control (n = 22) fetuses using LC-MS/MS.

Morphogenesis is transcriptionally coupled to neurogenesis during peripheral olfactory organ development.

Sense organs acquire their distinctive shapes concomitantly with the differentiation of sensory cells and neurons necessary for their function. Although our understanding of the mechanisms controlling morphogenesis and neurogenesis in these structures has grown, how these processes are coordinated remains largely unexplored. Neurogenesis in the zebrafish olfactory epithelium requires the bHLH proneural transcription factor Neurogenin 1 (Neurog1).

The low affinity p75 neurotrophin receptor is down-regulated in congenital anomalies of the kidney and the urinary tract: Possible involvement in early nephrogenesis.

Congenital Anomalies of the Kidney and of the Urinary Tract (CAKUT) cover a broad range of disorders including abnormal kidney development caused by defective nephrogenesis. Here we explored the possible involvement of the low affinity p75 neurotrophin receptor (p75NTR) in CAKUT and nephrogenesis. In mouse, p75NTR was highly expressed in fetal kidney, located within cortical early nephrogenic bodies, and decreased rapidly after birth.

Amniotic fluid peptides predict postnatal kidney survival in developmental kidney disease.

Although a rare disease, bilateral congenital anomalies of the kidney and urinary tract (CAKUT) are the leading cause of end stage kidney disease in children. Ultrasound-based prenatal prediction of postnatal kidney survival in CAKUT pregnancies is far from accurate. To improve prediction, we conducted a prospective multicenter peptidome analysis of amniotic fluid spanning 140 evaluable fetuses with CAKUT.

Cell-type heterogeneity in the early zebrafish olfactory epithelium is generated from progenitors within preplacodal ectoderm.

The zebrafish olfactory epithelium comprises a variety of neuronal populations, which are thought to have distinct embryonic origins. For instance, while ciliated sensory neurons arise from preplacodal ectoderm (PPE), previous lineage tracing studies suggest that both Gonadotropin releasing hormone 3 (Gnrh3) and microvillous sensory neurons derive from cranial neural crest (CNC). We find that the expression of Islet1/2 is restricted to Gnrh3 neurons associated with the olfactory epithelium.

Expression patterns of CREB binding protein (CREBBP) and its methylated species during zebrafish development.

Proper embryonic development requires a fine-tuned control of gene expression, which is achieved in part through the activity of transcription coactivators or corepressors. The nuclear coactivator cAMP-response element-binding protein (CREB) binding protein (CREBBP or CBP) interacts with numerous transcription factors and thereby plays a key role in various signaling pathways. Interestingly, in cell-based studies CREBBP activity is modulated by post-translational modifications such as methylation on arginine residues which is catalyzed by coactivator-associated arginine methyltransferase 1 (CARM1).

The methyltransferases PRMT4/CARM1 and PRMT5 control differentially myogenesis in zebrafish.

In vertebrates, skeletal myogenesis involves the sequential activation of myogenic factors to lead ultimately to the differentiation into slow and fast muscle fibers. How transcriptional co-regulators such as arginine methyltransferases PRMT4/CARM1 and PRMT5 control myogenesis in vivo remains poorly understood. Loss-of-function experiments using morpholinos against PRMT4/CARM1 and PRMT5 combined with in situ hybridization, quantitative polymerase chain reaction, as well as immunohistochemistry indicate a positive, but differential, role of these enzymes during myogenesis in vivo.

Two highly related regulatory subunits of PP2A exert opposite effects on TGF-beta/Activin/Nodal signalling.

We identify Balpha (PPP2R2A) and Bdelta (PPP2R2D), two highly related members of the B family of regulatory subunits of the protein phosphatase PP2A, as important modulators of TGF-beta/Activin/Nodal signalling that affect the pathway in opposite ways. Knockdown of Balpha in Xenopus embryos or mammalian tissue culture cells suppresses TGF-beta/Activin/Nodal-dependent responses, whereas knockdown of Bdelta enhances these responses. Moreover, in Drosophila, overexpression of Smad2 rescues a severe wing phenotype caused by overexpression of the single Drosophila PP2A B subunit Twins.

Methylation of Xilf3 by Xprmt1b alters its DNA, but not RNA, binding activity.

Modification of proteins by methylation has emerged as a key regulatory mechanism in many cellular processes, including gene control. Eighty to ninety percent of the arginine methylation in the cell is performed by the protein arginine methyl transferase PRMT1. ILF3, a protein involved in gene regulation at several levels, has been shown to be a substrate and regulator of PRMT1 in mammals.

Unexpected activities of Smad7 in Xenopus mesodermal and neural induction.

Neural induction is widely believed to be a direct consequence of inhibition of BMP pathways. Because of conflicting results and interpretations, we have re-examined this issue in Xenopus and chick embryos using the powerful and general TGFbeta inhibitor, Smad7, which inhibits both Smad1- (BMP) and Smad2- (Nodal/Activin) mediated pathways. We confirm that Smad7 efficiently inhibits phosphorylation of Smad1 and Smad2.

Kinesin-mediated transport of Smad2 is required for signaling in response to TGF-beta ligands.

During vertebrate development, Activin/Nodal-related ligands signal through Smad2, leading to its activation and accumulation in the nucleus. Here, we demonstrate that Smad2 constantly shuttles between the cytoplasm and nucleus both in early Xenopus embryo explants and in living zebrafish embryos, providing a mechanism whereby the intracellular components of the pathway constantly monitor receptor activity. We have gone on to demonstrate that an intact microtubule network and kinesin ATPase activity are required for Smad2 phosphorylation and nuclear accumulation in response to Activin/Nodal in early vertebrate embryos and TGF-beta in mammalian cells.

The Ca2+-induced methyltransferase xPRMT1b controls neural fate in amphibian embryo.

We have previously shown that an increase in intracellular Ca2+ is both necessary and sufficient to commit ectoderm to a neural fate in Xenopus embryos. However, the relationship between this Ca2+ increase and the expression of early neural genes has yet to be defined. Using a subtractive cDNA library between untreated and caffeine-treated animal caps, i.

[xMLP is an early response calcium target gene in neural determination in Xenopus laevis].

In vertebrates, neural induction occurs during gastrulation when ectodermal cells choose between two fates, neural and epidermal. In Xenopus, neural induction has been regarded as a default pathway as it occurs, in dorsal ectoderm, when ventralizing signals (mainly Bone Morphogenesis Proteins, BMPs, potent epidermal inducers) are inhibited by dorsalizing signals, including factors such as noggin, chordin, and follistatin. However, our previous studies demonstrated that an instructive signal triggered by the activation of L-type voltage-sensitive calcium channels, resulting in a transient increase in intracellular free calcium, appears to be a necessary and sufficient requirement to induce the competent ectoderm toward the neural pathway.