@phdthesis{Glasenapp2000,
  author    = {Glasenapp, Elisabeth ¬von¬},
  title     = {Lamin C2},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-3690},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2000},
  abstract  = {In der Kernlamina von Spermatozyten von Nagetieren sind die Lamin A-Genprodukte, Lamin A und C, durch eine meiosespezifische Splicingvariante ersetzt. Dieses Lamin C2 unterscheidet sich auffallend von den somatischen Varianten in Struktur, Menge und Verhalten. Durch eine ektopische Expression von Lamin C2 als EGFP-Lamin C2-Fusionsprotein in einer somatischen Zellinie zeigte sich, daß eine neuartige Hexapeptidsequenz (GNAEGR) am N-terminalen Ende des Proteins anstelle der C-terminal gelegenen CaaX-Box somatischer Lamine f{\"u}r die Interaktion mit der Kernh{\"u}lle verantwortlich ist. So erm{\"o}glicht eine posttranslationelle Myristylierung des ersten Glycins ein Membrantargeting, bei dem der hydrophobe Myristins{\"a}urerest vergleichbar dem hydrophoben Farnesylrest am Cystein der Caax-Box mit den Fetts{\"a}ureresten der Kernmembran interagiert. Die Deletion des Hexapeptids im Fusionsprotein EGFP-Lamin C2 und die seine N-terminale Insertion in das Fusionsprotein EGFP-Lamin C - es besitzt keine Caax-Box - best{\"a}tigt, daß allein das Hexapeptid das Membrantargeting steuert: Die Deletionsmutante EGFP-Lamin C2 bleibt diffus im Kern verteilt, w{\"a}hrend sich die Insertionsmutante EGFP-Lamin C im Bereich der Kernperipherie anreichert. Eine weitere Besonderheit stellt die Verteilung von Lamin C2 innerhalb der Kernh{\"u}lle dar, denn es verteilt sich nicht gleichm{\"a}ßig wie alle bisher bekannten Lamine, sondern bildet zahlreiche Aggregate. Nicht nur in der Kernh{\"u}lle von Spermatozyten, sondern auch als Fusionsprotein in somatischen Zellen exprimiert, zeigt Lamin C2 diese Akkumulationen. {\"U}berraschenderweise treten die Synaptonemal-komplexenden nur im Bereich dieser Lamin C2-Aggregate mit der Kernh{\"u}lle in Kontakt. Es wird daher postuliert, daß die Lamin C2-Aggregate der lokalen Verst{\"a}rkung der Kernh{\"u}lle dienen und wichtig f{\"u}r die auf die Prophase beschr{\"a}nkte Anheftung der SC an die Kernh{\"u}lle sind. Da zudem in einer Kurzzeitkultur von Pachyt{\"a}nspermatozyten, in der die Prophase k{\"u}nstlich beschleunigt wird, gezeigt werden konnte, daß Lamin C2 mit Ende der Prophase I noch vor dem Aufl{\"o}sen der eigentlichen Kernh{\"u}lle nicht mehr nachweisbar ist, scheint ein Zusammenhang zwischen Lamin C2 in der Kernh{\"u}lle und der Umorganisation des genetischen Materials zu bestehen.},
  subject      = {Ratte},
  language  = {de}
}
@article{NandaSchoriesSimeonovetal.2022,
  author    = {Nanda, Indrajit and Schories, Susanne and Simeonov, Ivan and Adolfi, Mateus Contar and Du, Kang and Steinlein, Claus and Alsheimer, Manfred and Haaf, Thomas and Schartl, Manfred},
  title     = {Evolution of the degenerated Y-chromosome of the swamp guppy, Micropoecilia picta},
  series = {Cells},
  volume    = {11},
  journal   = {Cells},
  number    = {7},
  issn      = {2073-4409},
  doi       = {10.3390/cells11071118},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-267242},
  year      = {2022},
  abstract  = {The conspicuous colour sexual dimorphism of guppies has made them paradigmatic study objects for sex-linked traits and sex chromosome evolution. Both the X- and Y-chromosomes of the common guppy (Poecilia reticulata) are genetically active and homomorphic, with a large homologous part and a small sex specific region. This feature is considered to emulate the initial stage of sex chromosome evolution. A similar situation has been documented in the related Endler's and Oropuche guppies (P. wingei, P. obscura) indicating a common origin of the Y in this group. A recent molecular study in the swamp guppy (Micropoecilia. picta) reported a low SNP density on the Y, indicating Y-chromosome deterioration. We performed a series of cytological studies on M. picta to show that the Y-chromosome is quite small compared to the X and has accumulated a high content of heterochromatin. Furthermore, the Y-chromosome stands out in displaying CpG clusters around the centromeric region. These cytological findings evidently illustrate that the Y-chromosome in M. picta is indeed highly degenerated. Immunostaining for SYCP3 and MLH1 in pachytene meiocytes revealed that a substantial part of the Y remains associated with the X. A specific MLH1 hotspot site was persistently marked at the distal end of the associated XY structure. These results unveil a landmark of a recombining pseudoautosomal region on the otherwise strongly degenerated Y chromosome of M. picta. Hormone treatments of females revealed that, unexpectedly, no sexually antagonistic color gene is Y-linked in M. picta. All these differences to the Poecilia group of guppies indicate that the trajectories associated with the evolution of sex chromosomes are not in parallel.},
  language  = {en}
}
@article{DedukhDaCruzKneitzetal.2022,
  author    = {Dedukh, Dmitrij and Da Cruz, Irene and Kneitz, Susanne and Marta, Anatolie and Ormanns, Jenny and Tichop{\´a}d, Tom{\´a}š and Lu, Yuan and Alsheimer, Manfred and Janko, Karel and Schartl, Manfred},
  title     = {Achiasmatic meiosis in the unisexual Amazon molly, Poecilia formosa},
  series = {Chromosome Research},
  volume    = {30},
  journal   = {Chromosome Research},
  number    = {4},
  doi       = {10.1007/s10577-022-09708-2},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-325128},
  pages     = {443-457},
  year      = {2022},
  abstract  = {Unisexual reproduction, which generates clonal offspring, is an alternative strategy to sexual breeding and occurs even in vertebrates. A wide range of non-sexual reproductive modes have been described, and one of the least understood questions is how such pathways emerged and how they mechanistically proceed. The Amazon molly, Poecilia formosa, needs sperm from males of related species to trigger the parthenogenetic development of diploid eggs. However, the mechanism, of how the unreduced female gametes are produced, remains unclear. Cytological analyses revealed that the chromosomes of primary oocytes initiate pachytene but do not proceed to bivalent formation and meiotic crossovers. Comparing ovary transcriptomes of P. formosa and its sexual parental species revealed expression levels of meiosis-specific genes deviating from P. mexicana but not from P. latipinna. Furthermore, several meiosis genes show biased expression towards one of the two alleles from the parental genomes. We infer from our data that in the Amazon molly diploid oocytes are generated by apomixis due to a failure in the synapsis of homologous chromosomes. The fact that this failure is not reflected in the differential expression of known meiosis genes suggests the underlying molecular mechanism may be dysregulation on the protein level or misexpression of a so far unknown meiosis gene, and/or hybrid dysgenesis because of compromised interaction of proteins from diverged genomes.},
  language  = {en}
}