Prpic-Schäper, Nikola-Michael

[["dc.bibliographiccitation.firstpage","361"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","Development Genes and Evolution"],["dc.bibliographiccitation.lastpage","370"],["dc.bibliographiccitation.volume","218"],["dc.contributor.author","Janssen, Ralf"],["dc.contributor.author","Budd, Graham E."],["dc.contributor.author","Damen, Wim G. M."],["dc.contributor.author","Prpic, Nikola-Michael"],["dc.date.accessioned","2018-11-07T11:13:19Z"],["dc.date.available","2018-11-07T11:13:19Z"],["dc.date.issued","2008"],["dc.description.abstract","The correlation between dorsal and ventral segmental units in diplopod myriapods is complex and disputed. Recent results with engrailed (en), hedgehog (hh), wingless (wg), and cubitus-interruptus (ci) have shown that the dorsal segments are patterned differently from the ventral segments. Ventrally, gene expression is compatible with the classical autoregulatory loop known from Drosophila to specify the parasegment boundary. In the dorsal segments, however, this Wg/Hh autoregulatory loop cannot be present because the observed gene expression patterns argue against the involvement of Wg signalling. In this paper, we present further evidence against an involvement of Wg signalling in dorsal segmentation and propose a hypothesis about how dorsal segmental boundaries may be controlled in a wg-independent way. We find that (1) the Notum gene, a modulator of the Wg gradient in Drosophila, is not expressed in the dorsal segments. (2) The H15/midline gene, a repressor of Wg action in Drosophila, is not expressed in the dorsal segments, except for future heart tissue. (3) The patched (ptc) gene, which encodes a Hh receptor, is strongly expressed in the dorsal segments, which is incompatible with Wg-Hh autoregulation. The available data suggest that anterior-posterior (AP) boundary formation in dorsal segments could instead rely on Dpp signalling rather than Wg signalling. We present a hypothesis that relies on Hh-mediated activation of Dpp signalling and optomotor-blind (omb) expression to establish the dorsal AP boundary (the future tergite boundary). The proposed mechanism is similar to the mechanism used to establish the AP boundary in Drosophila wings and ventral pleura."],["dc.identifier.doi","10.1007/s00427-008-0231-2"],["dc.identifier.isi","000257395200003"],["dc.identifier.pmid","18592266"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/53865"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Springer"],["dc.relation.issn","0949-944X"],["dc.title","Evidence for Wg-independent tergite boundary formation in the millipede Glomeris marginata"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","21"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Evolution & Development"],["dc.bibliographiccitation.lastpage","33"],["dc.bibliographiccitation.volume","17"],["dc.contributor.author","Janssen, Ralf"],["dc.contributor.author","Jørgensen, Mette Christine"],["dc.contributor.author","Prpic, Nikola-Michael"],["dc.contributor.author","Budd, Graham E."],["dc.date.accessioned","2018-11-07T10:03:41Z"],["dc.date.available","2018-11-07T10:03:41Z"],["dc.date.issued","2015"],["dc.description.abstract","Onychophorans (velvet worms) are closely related to the arthropods, but their limb morphology represents a stage before arthropodization (i.e., the segmentation of the limbs). We investigated the expression of onychophoran homologs of genes that are involved in dorso-ventral (DV) and proximo-distal (PD) limb patterning in arthropods. We find that the two onychophoran optomotor-blind (omb) genes, omb-1 and omb-2, are both expressed in conserved patterns in the dorsal ectoderm of the limbs, including the onychophoran antennae (the frontal appendages). Surprisingly, the expression of decapentaplegic (dpp), which acts upstream of omb in Drosophila, is partially reversed in onychophoran limbs compared to its expression in arthropods. A conserved feature of dpp expression in arthropods and onychophorans, however, is the prominent expression of dpp in the tips of developing limbs, which, therefore, may represent the ancestral pattern. The expression patterns of wingless (wg) and H15 are very diverged in onychophorans. The wg gene is only expressed in the limb tips and the single H15 gene is expressed in a few dorsal limb cells, but not on the ventral side. The expression of wg and dpp at the limb tips is one of the three possible alternatives predicted by the topology model of arthropod limb patterning and is, thus, compatible with a conserved function of wg and dpp in the patterning of the PD axis. On the other hand, DV limb gene expression is less conserved, and the specification of ventral fate appears to involve neither wg nor H15 expression."],["dc.identifier.doi","10.1111/ede.12107"],["dc.identifier.isi","000349042300003"],["dc.identifier.pmid","25627711"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/38530"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1525-142X"],["dc.relation.issn","1520-541X"],["dc.title","Aspects of dorso-ventral and proximo-distal limb patterning in onychophorans"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","363"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","Evolution & Development"],["dc.bibliographiccitation.lastpage","372"],["dc.bibliographiccitation.volume","12"],["dc.contributor.author","Janssen, Ralf"],["dc.contributor.author","Eriksson, Bo Joakim"],["dc.contributor.author","Budd, Graham E."],["dc.contributor.author","Akam, Michael"],["dc.contributor.author","Prpic, Nikola-Michael"],["dc.date.accessioned","2018-11-07T08:41:38Z"],["dc.date.available","2018-11-07T08:41:38Z"],["dc.date.issued","2010"],["dc.description.abstract","P>In arthropods, such as Drosophila melanogaster, the leg gap genes homothorax (hth), extradenticle (exd), dachshund (dac), and Distal-less (Dll) regionalize the legs in order to facilitate the subsequent segmentation of the legs. We have isolated homologs of all four leg gap genes from the onychophoran Euperipatoides kanangrensis and have studied their expression. We show that leg regionalization takes place in the legs of onychophorans even though they represent simple and nonsegmented appendages. This implies that leg regionalization evolved for a different function and was only later co-opted for a role in leg segmentation. We also show that the leg gap gene patterns in onychophorans (especially of hth and exd) are similar to the patterns in crustaceans and insects, suggesting that this is the plesiomorphic state in arthropods. The reversed hth and exd patterns in chelicerates and myriapods are therefore an apomorphy for this group, the Myriochelata, lending support to the Myriochelata and Tetraconata clades in arthropod phylogeny."],["dc.identifier.doi","10.1111/j.1525-142X.2010.00423.x"],["dc.identifier.isi","000279440800004"],["dc.identifier.pmid","20618432"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/19518"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-blackwell"],["dc.relation.issn","1520-541X"],["dc.title","Gene expression patterns in an onychophoran reveal that regionalization predates limb segmentation in pan-arthropods"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","374"],["dc.bibliographiccitation.journal","BMC Evolutionary Biology"],["dc.bibliographiccitation.volume","10"],["dc.contributor.author","Janssen, Ralf"],["dc.contributor.author","Le Gouar, Martine"],["dc.contributor.author","Pechmann, Matthias"],["dc.contributor.author","Poulin, Francis"],["dc.contributor.author","Bolognesi, Renata"],["dc.contributor.author","Schwager, Evelyn E."],["dc.contributor.author","Hopfen, Corinna"],["dc.contributor.author","Colbourne, John K."],["dc.contributor.author","Budd, Graham E."],["dc.contributor.author","Brown, Susan J."],["dc.contributor.author","Prpic, Nikola-Michael"],["dc.contributor.author","Kosiol, Carolin"],["dc.contributor.author","Vervoort, Michel"],["dc.contributor.author","Damen, Wim G. M."],["dc.contributor.author","Balavoine, Guillaume"],["dc.contributor.author","McGregor, Alistair P."],["dc.date.accessioned","2018-11-07T08:36:03Z"],["dc.date.available","2018-11-07T08:36:03Z"],["dc.date.issued","2010"],["dc.description.abstract","Background: The Wnt genes encode secreted glycoprotein ligands that regulate a wide range of developmental processes, including axis elongation and segmentation. There are thirteen subfamilies of Wnt genes in metazoans and this gene diversity appeared early in animal evolution. The loss of Wnt subfamilies appears to be common in insects, but little is known about the Wnt repertoire in other arthropods, and moreover the expression and function of these genes have only been investigated in a few protostomes outside the relatively Wnt-poor model species Drosophila melanogaster and Caenorhabditis elegans. To investigate the evolution of this important gene family more broadly in protostomes, we surveyed the Wnt gene diversity in the crustacean Daphnia pulex, the chelicerates Ixodes scapularis and Achaearanea tepidariorum, the myriapod Glomeris marginata and the annelid Platynereis dumerilii. We also characterised Wnt gene expression in the latter three species, and further investigated expression of these genes in the beetle Tribolium castaneum. Results: We found that Daphnia and Platynereis both contain twelve Wnt subfamilies demonstrating that the common ancestors of arthropods, ecdysozoans and protostomes possessed all members of all Wnt subfamilies except Wnt3. Furthermore, although there is striking loss of Wnt genes in insects, other arthropods have maintained greater Wnt gene diversity. The expression of many Wnt genes overlap in segmentally reiterated patterns and in the segment addition zone, and while these patterns can be relatively conserved among arthropods and the annelid, there have also been changes in the expression of some Wnt genes in the course of protostome evolution. Nevertheless, our results strongly support the parasegment as the primary segmental unit in arthropods, and suggest further similarities between segmental and parasegmental regulation by Wnt genes in annelids and arthropods respectively. Conclusions: Despite frequent losses of Wnt gene subfamilies in lineages such as insects, nematodes and leeches, most protostomes have probably maintained much of their ancestral repertoire of twelve Wnt genes. The maintenance of a large set of these ligands could be in part due to their combinatorial activity in various tissues"],["dc.identifier.doi","10.1186/1471-2148-10-374"],["dc.identifier.isi","000287576000002"],["dc.identifier.pmid","21122121"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/18218"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Biomed Central Ltd"],["dc.relation.issn","1471-2148"],["dc.title","Conservation, loss, and redeployment of Wnt ligands in protostomes: implications for understanding the evolution of segment formation"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","143"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Evolution & Development"],["dc.bibliographiccitation.lastpage","154"],["dc.bibliographiccitation.volume","10"],["dc.contributor.author","Janssen, Ralf"],["dc.contributor.author","Feitosa, Natalia M."],["dc.contributor.author","Damen, Wim G. M."],["dc.contributor.author","Prpic, Nikola-Michael"],["dc.date.accessioned","2018-11-07T11:17:35Z"],["dc.date.available","2018-11-07T11:17:35Z"],["dc.date.issued","2008"],["dc.description.abstract","Dorsoventral axis formation in the legs of the fly Drosophila melanogaster requires the T-box genes optomotor-blind (omb) and H15. Evolutionary conservation of the patterning functions of these genes is unclear, because data on H15 expression in the spider Cupiennius salei did not support a general role of H15 in ventral fate specification. However, H15 has a paralogous gene, midline (mid) in Drosophila and H15 duplicates are also present in Cupiennius and the millipede Glomeris marginata. H15 therefore seems to have been subject to gene duplication opening the possibility that the previous account on Cupiennius has overlooked one or several paralogs. We have studied omb- and H15-related genes in two additional spider species, Tegenaria atrica and Achearanea tepidariorum and show that in both species one of the H15 genes belongs to a third group of spider H15 genes that has an expression pattern very similar to the H15 pattern in Drosophila. The expression patterns of all omb-related genes are also very similar to the omb expression pattern in Drosophila. These data suggest that the dorsoventral patterning functions of omb and H15 are conserved in the arthropods and that the previous conclusions were based on an incomplete data set in Cupiennius. Our results emphasize the importance of a broad taxon sampling in comparative studies."],["dc.identifier.isi","000253707300003"],["dc.identifier.pmid","18315808"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/54840"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Blackwell Publishing"],["dc.relation.issn","1520-541X"],["dc.title","The T-box genes H15 and optomotor-blind in the spiders Cupiennius salei, Tegenaria atrica and Achaearanea tepidariorum and the dorsoventral axis of arthropod appendages"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]