{"title":"Cell biological mechanisms regulating chick neurogenesis.","authors":"Ioannis Kasioulis, Kate G Storey","doi":"10.1387/ijdb.170268ks","DOIUrl":"https://doi.org/10.1387/ijdb.170268ks","url":null,"abstract":"<p><p>Signalling pathways that regulate neural progenitor proliferation and neuronal differentiation have been identified. However, we know much less about how transduction of such signals is regulated within neuroepithelial cells to direct cell fate choice during mitosis and subsequent neuronal differentiation. Here we review recent advances in the experimentally amenable chick embryo, which reveal that this involves association of signalling pathway components with cell biological entities, including mitotic centrosomes and ciliary structures. This includes changing centrosomal localization of protein kinase A, which regulates Sonic hedgehog signalling and so neural progenitor status, and Mindbomb1, a mediator of Notch ligand activation, which promotes Notch signalling in neighbouring cells, and so is active in presumptive neurons. We further review cell biological events that underlie the later step of neuronal delamination, during which a newborn neuron detaches from its neighbouring cells and undergoes a process known as apical abscission. This involves inter-dependent actin and microtubule dynamics and includes dissociation of the centrosome from the ciliary membrane, which potentially alters the signalling repertoire of this now post-mitotic cell. Open questions and future directions are discussed along with technological advances which improve accuracy of gene manipulation, monitoring of protein dynamics and quantification of cell biological processes in living tissues.</p>","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":" ","pages":"167-175"},"PeriodicalIF":0.7,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1387/ijdb.170268ks","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"35975866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A life in Science with the avian embryo.","authors":"Nicole M Le Douarin","doi":"10.1387/ijdb.170287NL","DOIUrl":"https://doi.org/10.1387/ijdb.170287NL","url":null,"abstract":"<p><p>My career in research was a second thought. I first (during 8 years) worked as a secondary school teacher and after 4-5 years, during which my two daughters were born, I found a way to escape from what was to be a lifetime job. For two years, my initiation to research was limited to the free time left by my teaching duties. This period of time was a bit \"complicated\" but not enough to prevent me to realize that research was really what I wanted to do for the rest of my life… And this was when I became acquainted with the chick embryo. This companionship later became extended to another representative of the avian world: the quail (Coturnix coturnix japonica). I recall in the following lines a survey of scientific stories that came out from my association with these precious animals, ... not without a feeling of gratitude.</p>","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":" ","pages":"19-33"},"PeriodicalIF":0.7,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1387/ijdb.170287NL","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"35975869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Aurora-A: an expedition to the pole of the spindle in Xenopus egg extracts.","authors":"J. Kubiak, C. Prigent","doi":"10.1387/IJDB.160189JK","DOIUrl":"https://doi.org/10.1387/IJDB.160189JK","url":null,"abstract":"The aim of this short review is to describe the contribution of Xenopus laevis egg extracts to the discovery and understanding of the regulation and function of the serine/threonine kinase Aurora-A. The power of these extracts to recapitulate cell cycle events makes them a precious tool to decipher complex biological processes at the molecular level, including the mechanisms that affect Aurora-A (post-translational modifications) and mechanisms in which Aurora-A plays a crucial role (bipolar spindle assembly). We focus on the results obtained in cell-free extracts, but we also give an updated overview of Aurora A functions found in other systems.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"38 1","pages":"255-261"},"PeriodicalIF":0.0,"publicationDate":"2016-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74498907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Dȩbowski, Mohammed El Dika, J. Malejczyk, R. Zdanowski, C. Prigent, J. Tassan, M. Kloc, M. Lachowicz, J. Kubiak
{"title":"Flexibility vs. robustness in cell cycle regulation of timing of M-phase entry in Xenopus laevis embryo cell-free extract.","authors":"M. Dȩbowski, Mohammed El Dika, J. Malejczyk, R. Zdanowski, C. Prigent, J. Tassan, M. Kloc, M. Lachowicz, J. Kubiak","doi":"10.1387/IJDB.160134JK","DOIUrl":"https://doi.org/10.1387/IJDB.160134JK","url":null,"abstract":"During the cell cycle, cyclin dependent kinase 1 (CDK1) and protein phosphatase 2A (PP2A) play major roles in the regulation of mitosis. CDK1 phosphorylates a series of substrates triggering M-phase entry. Most of these substrates are dephosphorylated by PP2A. To allow phosphorylation of CDK1 substrates, PP2A is progressively inactivated upon M-phase entry. We have shown previously that the interplay between these two activities determines the timing of M-phase entry. Slight diminution of CDK1 activity by the RO3306 inhibitor delays M-phase entry in a dose-dependent manner in Xenopus embryo cell-free extract, while reduction of PP2A activity by OA inhibitor accelerates this process also in a dose-dependent manner. However, when a mixture of RO3306 and OA is added to the extract, an intermediate timing of M-phase entry is observed. Here we use a mathematical model to describe and understand this interplay. Simulations showing acceleration and delay in M-phase entry match previously described experimental data. CDC25 phosphatase is a major activator of CDK1 and acts through CDK1 Tyr15 and Thr14 dephosphorylation. Addition of CDC25 activity to our mathematical model was also consistent with our experimental results. To verify whether our assumption that the dynamics of CDC25 activation used in this model are the same in all experimental variants, we analyzed the dynamics of CDC25 phosphorylation, which reflect its activation. We confirm that these dynamics are indeed very similar in control extracts and when RO3306 and OA are present separately. However, when RO3306 and OA are added simultaneously to the extract, activation of CDC25 is slightly delayed. Integration of this parameter allowed us to improve our model. Furthermore, the pattern of CDK1 dephosphorylation on Tyr15 showed that the real dynamics of CDK1 activation are very similar in all experimental variants. The model presented here accurately describes, in mathematical terms, how the interplay between CDK1, PP2A and CDC25 controls the flexible timing of M-phase entry.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"54 2 1","pages":"305-314"},"PeriodicalIF":0.0,"publicationDate":"2016-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74317937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"MPF, starfish oocyte and cell-free extract in the background - an interview with Takeo Kishimoto.","authors":"J. Kubiak, T. Kishimoto","doi":"10.1387/IJDB.160348JK","DOIUrl":"https://doi.org/10.1387/IJDB.160348JK","url":null,"abstract":"Professor Takeo Kishimoto's research has an enormous impact on the cell cycle field. Although his favorite model has always been a starfish oocyte, he has used many other model organisms in his research. Cell-free extracts have been wildly used in his laboratory as a very useful tool to answer cell cycle research questions. Recently, professor Kishimoto discovered the identity of the M-phase promoting factor (MPF) that was thought for years to be cyclin-dependent kinase 1 (CDK1). However, Takeo Kishimoto found that MPF consists in fact of two kinases: CDK1 and Greatwall kinase. While CDK1 phosphorylates mitotic substrates, Greatwall kinase allows these substrates to persist in their phosphorylated state because it regulates phosphatase PP2A, which dephosphorylates the majority of CDK1 substrates. When I started to interview Prof. Kishimoto, I was mostly interested in his experiences with cell-free extracts. However, as you will see below we almost immediately turned to the problem of the identity of MPF. This is fully understandable because the identity of MPF seems to be a major interest in Takeo's scientific career. I hope readers will enjoy this interview and will be able to learn about many aspects of scientific research, which do not usually appear in regular research papers.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"49 1","pages":"193-200"},"PeriodicalIF":0.0,"publicationDate":"2016-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88717138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Chaperone-mediated chromatin assembly and transcriptional regulation in Xenopus laevis.","authors":"Takashi Onikubo, D. Shechter","doi":"10.1387/IJDB.130188DS","DOIUrl":"https://doi.org/10.1387/IJDB.130188DS","url":null,"abstract":"Chromatin is the complex of DNA and histone proteins that is the physiological form of the eukaryotic genome. Chromatin is generally repressive for transcription, especially so during early metazoan development when maternal factors are explicitly in control of new zygotic gene expression. In the important model organism Xenopus laevis, maturing oocytes are transcriptionally active with reduced rates of chromatin assembly, while laid eggs and fertilized embryos have robust rates of chromatin assembly and are transcriptionally repressed. As the DNA-to-cytoplasmic ratio decreases approaching the mid-blastula transition (MBT) and the onset of zygotic genome activation (ZGA), the chromatin assembly process changes with the concomitant reduction in maternal chromatin components. Chromatin assembly is mediated in part by histone chaperones that store maternal histones and release them into new zygotic chromatin. Here, we review literature on chromatin and transcription in frog embryos and cell-free extracts and highlight key insights demonstrating the roles of maternal and zygotic histone deposition and their relationship with transcriptional regulation. We explore the central historical and recent literature on the use of Xenopus embryos and the key contributions provided by experiments in cell-free oocyte and egg extracts for the interplay between histone chaperones, chromatin assembly, and transcriptional regulation. Ongoing and future studies in Xenopus cell free extracts will likely contribute essential new insights into the interplay between chromatin assembly and transcriptional regulation.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"1 1","pages":"271-276"},"PeriodicalIF":0.0,"publicationDate":"2016-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74945922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Vigneron, Perle Robert, Khaled Hached, Lena Sundermann, S. Charrasse, J. Labbé, A. Castro, T. Lorca
{"title":"The master Greatwall kinase, a critical regulator of mitosis and meiosis.","authors":"S. Vigneron, Perle Robert, Khaled Hached, Lena Sundermann, S. Charrasse, J. Labbé, A. Castro, T. Lorca","doi":"10.1387/IJDB.160155TL","DOIUrl":"https://doi.org/10.1387/IJDB.160155TL","url":null,"abstract":"Entry into mitosis requires the coordinated activation of various protein kinases and phosphatases that together activate sequential signaling pathways allowing entry, progression and exit of mitosis. The limiting step is thought to be the activation of the mitotic Cdk1-cyclin B kinase. However, this model has recently evolved with new data showing that in addition to the Cdk1-cyclin B complex, Greatwall (Gwl) kinase is also required to enter into and maintain mitosis. This new concept proposes that entry into mitosis is now based on the combined activation of both kinases Cdk1-cyclin B and Gwl, the former promoting massive phosphorylation of mitotic substrates and the latter inhibiting PP2A-B55 phosphatase responsible for dephosphorylation of these substrates. Activated Gwl phosphorylates both Arpp19 and ENSA, which associate and inhibit PP2A-B55. This pathway seems relatively well conserved from yeast to humans, although some differences appear based on models or techniques used. While Gwl is activated by phosphorylation, its inactivation requires dephosphorylation of critical residues. Several phosphatases such as PP1, PP2A-B55 and FCP1 are required to control the dephosphorylation and inactivation of Gwl and a properly regulated mitotic exit. Gwl has also been reported to be involved in cancer processes and DNA damage recovery. These new findings support the idea that the Gwl-Arpp19/ENSA-PP2A-B55 pathway is essential to achieve an efficient division of cells and to maintain genomic stability.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"49 1","pages":"245-254"},"PeriodicalIF":0.0,"publicationDate":"2016-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79092079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Expressional characterization of mRNA (guanine-7) methyltransferase (rnmt) during early development of Xenopus laevis.","authors":"Ashwin Lokapally, Sanjeeva Metikala, T. Hollemann","doi":"10.1387/ijdb.150409th","DOIUrl":"https://doi.org/10.1387/ijdb.150409th","url":null,"abstract":"Methylation of the guanosine cap structure at the 5' end of mRNA is essential for efficient translation of all eukaryotic cellular mRNAs, gene expression and cell viability and promotes transcription, splicing, polyadenylation and nuclear export of mRNA. In the current study, we present the spatial expression pattern of the Xenopus laevis rnmt homologue. A high percentage of protein sequence similarity, especially within the methyltransferase domain, as well as an increased expression in the cells of the transcriptionally active stages, suggests a conserved RNA cap methylation function. Spatial expression analysis identified expression domains in the brain, the retina, the lens, the otic vesicles and the branchial arches.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"21 1","pages":"65-9"},"PeriodicalIF":0.0,"publicationDate":"2016-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79259730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"In Memoriam - Prof. G. Barry Pierce (1925-2015).","authors":"I. Damjanov","doi":"10.1387/ijdb.160014id","DOIUrl":"https://doi.org/10.1387/ijdb.160014id","url":null,"abstract":"Gordon Barry Pierce, my great mentor and long-time friend died in November 2015 at the age of 90 years. We will all miss him. What we are left with, however, are reminiscences of moments we spent with him, his jokes and stories to be retold and passed along, titbits of advice, and pearls of his common-sense Canadian wisdom. A vision of a better world to which he contributed so much. Scientific contributions too numerous to list, many of which had major impact on us who were interested in the same problems as he was. Seminal discoveries that impacted the progress in several fields of scientific endeavor. Major new concepts of oncology and developmental biology that opened new vistas and revolutionized our thinking about the crucial problems of biology and medicine. Unforgettable seminars and lectures. Unquenchable love for science. And much more that, nevertheless, can be summarized in two wondrous exclamations: What a man! What a life!","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"1 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2016-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73131362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Christian Mukendi, N. Dean, Rushil Lala, J. Smith, M. Bronner, N. Nikitina
{"title":"Evolution of the vertebrate claudin gene family: insights from a basal vertebrate, the sea lamprey.","authors":"Christian Mukendi, N. Dean, Rushil Lala, J. Smith, M. Bronner, N. Nikitina","doi":"10.1387/ijdb.150364nn","DOIUrl":"https://doi.org/10.1387/ijdb.150364nn","url":null,"abstract":"Claudins are major constituents of tight junctions, contributing both to their intercellular sealing and selective permeability properties. While claudins and claudin-like molecules are present in some invertebrates, the association of claudins with tight junctions has been conclusively documented only in vertebrates. Here we report the sequencing, phylogenetic analysis and comprehensive spatiotemporal expression analysis of the entire claudin gene family in the basal extant vertebrate, the sea lamprey. Our results demonstrate that clear orthologues to about half of all mammalian claudins are present in the lamprey, suggesting that at least one round of whole genome duplication contributed to the diversification of this gene family. Expression analysis revealed that claudins are expressed in discrete and specific domains, many of which represent vertebrate-specific innovations, such as in cranial ectodermal placodes and the neural crest; whereas others represent structures characteristic of chordates, e.g. pronephros, notochord, somites, endostyle and pharyngeal arches. By comparing the embryonic expression of claudins in the lamprey to that of other vertebrates, we found that ancestral expression patterns were often preserved in higher vertebrates. Morpholino mediated loss of Cldn3b demonstrated a functional role for this protein in placode and pharyngeal arch morphogenesis. Taken together, our data provide novel insights into the origins and evolution of the claudin gene family and the significance of claudin proteins in the evolution of vertebrates.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"5 2 1","pages":"39-51"},"PeriodicalIF":0.0,"publicationDate":"2016-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91230612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}