ALBERT

Description:    Fluorescence in situ hybridization (FISH) is a useful tool for physical mapping of chromosomes and studying evolutionary chromosome rearrangements. Here we report a robust method for single-copy gene FISH for wheat. FISH probes were developed from cDNA of cytosolic acetyl-CoA carboxylase (ACCase) gene ( Acc-2 ) and mapped on chromosomes of bread wheat, Triticum aestivum L. (2 n  = 6 x  = 42, AABBDD), and related diploid and tetraploid species. Another nine full-length (FL) cDNA FISH probes were mapped and used to identify chromosomes of wheat species. The Acc-2 probe was detected on the long arms of each of the homoeologous group 3 chromosomes (3A, 3B, and 3D), on 5DL and 4AL of bread wheat, and on homoeologous and nonhomoeologous chromosomes of other species. In the species tested, FISH detected more Acc-2 gene or pseudogene sites than previously found by PCR and Southern hybridization analyses and showed presence/absence polymorphism of Acc-2 sequences. FISH with the Acc-2 probe revealed the 4A–5A translocation, shared by several related diploid and polyploid species and inherited from an ancestral A-genome species, and the T. timopheevii -specific 4A t –3A t translocation. Content Type Journal Article Category Research Article Pages 1-15 DOI 10.1007/s00412-012-0384-7 Authors Tatiana V. Danilova, Wheat Genetic and Genomic Resources Center, Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA Bernd Friebe, Wheat Genetic and Genomic Resources Center, Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA Bikram S. Gill, Wheat Genetic and Genomic Resources Center, Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA Journal Chromosoma Online ISSN 1432-0886 Print ISSN 0009-5915

Description:    The condensation state of chromosomes is a critical parameter in multiple processes within the cell. Failures in the maintenance of appropriate condensation states may lead to genomic instability, mis-expression of genes, and a number of disease states. During cell proliferation, replication of DNA represents an ongoing challenge for chromosome packaging as DNA must be unpackaged for replication and then faithfully repackaged. An integral member of the DNA replication machinery is the GINS complex which has been shown to stabilize the CMG complex which is required for processivity of the Mcm2-7 helicase complex during S phase. Through examination of the phenotypes associated with a null mutation in Psf2 , a member of the evolutionarily conserved GINS complex, we find that Drosophila Psf2 likely has a role in establishing chromosome condensation and that the defects associated with this mis-condensation impact M phase progression, genomic stability, and transcriptional regulation. Content Type Journal Article Category Research Article Pages 1-12 DOI 10.1007/s00412-012-0383-8 Authors Jeffrey P. Chmielewski, Department of Biology, East Carolina University, Greenville, NC 27858, USA Laura Henderson, Janelia Farm Research Campus HHMI, Ashburn, VA 20147, USA Charlotte M. Smith, Department of Biology, East Carolina University, Greenville, NC 27858, USA Tim W. Christensen, Department of Biology, East Carolina University, Greenville, NC 27858, USA Journal Chromosoma Online ISSN 1432-0886 Print ISSN 0009-5915

Description:    With the goal of creating two genetically identical daughter cells, cell division culminates in the equal segregation of sister chromatids. This phase of cell division is monitored by a cell cycle checkpoint known as the spindle assembly checkpoint (SAC). The SAC actively prevents chromosome segregation while one or more chromosomes, or more accurately kinetochores, remain unattached to the mitotic spindle. Such unattached kinetochores recruit SAC proteins to assemble a diffusible anaphase inhibitor. Kinetochores stop production of this inhibitor once microtubules (MTs) of the mitotic spindle are bound, but productive attachment of all kinetochores is required to satisfy the SAC, initiate anaphase, and exit from mitosis. Although mechanisms of kinetochore signaling and SAC inhibitor assembly and function have received the bulk of attention in the past two decades, recent work has focused on the principles of SAC silencing. Here, we review the mechanisms that silence SAC signaling at the kinetochore, and in particular, how attachment to spindle MTs and biorientation on the mitotic spindle may turn off inhibitor generation. Future challenges in this area are highlighted towards the goal of building a comprehensive molecular model of this process. Content Type Journal Article Category Review Pages 1-17 DOI 10.1007/s00412-012-0378-5 Authors Geert J. P. L. Kops, Department of Medical Oncology and Department of Molecular Cancer Research, University Medical Center Utrecht, Utrecht, The Netherlands Jagesh V. Shah, Department of Systems Biology, Harvard Medical School and Renal Division, Brigham and Women’s Hospital, Boston, MA, USA Journal Chromosoma Online ISSN 1432-0886 Print ISSN 0009-5915

Description:    The functional output of the genome is closely dependent on its organization within the nucleus, which ranges from the 10-nm chromatin fiber to the three-dimensional arrangement of this fiber in the nuclear space. Recent observations suggest that intra- and inter-chromosomal interactions between distant sequences underlie several aspects of transcription regulatory processes. These contacts can bring enhancers close to their target genes or prevent inappropriate interactions between regulatory sequences via insulators. In addition, intra- and inter-chromosomal interactions can bring co-activated or co-repressed genes to the same nuclear location. Recent technological advances have made it possible to map long-range cis and trans interactions at relatively high resolution. This information is being used to develop three-dimensional maps of the arrangement of the genome in the nucleus and to understand causal relationships between nuclear structure and function. Content Type Journal Article Category Review Pages 107-116 DOI 10.1007/s00412-011-0352-7 Authors Chunhui Hou, Department of Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA Victor G. Corces, Department of Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA Journal Chromosoma Online ISSN 1432-0886 Print ISSN 0009-5915 Journal Volume Volume 121 Journal Issue Volume 121, Number 2

Description:    The male hypermethylated (MHM) region of the chicken Z chromosome encodes a non-coding RNA that is expressed only in females. The MHM sequence is found only in galliform birds, and Z genes near this region show an unusual degree of dosage compensation between males and females despite the overall low level of dosage compensation in Z chromosome gene expression in birds. Here we report that the MHM locus shows a dramatic sex difference in the configuration of chromatin, open in females and condensed in males, based on DNA fluorescent in situ hybridization of an MHM probe in interphase nuclei. The demethylating agent 5-aza-cytidine causes an asymmetric effect on the two Z chromosomes of males, altering the chromatin configuration, MHM RNA expression, and H4K16Ac modification, suggesting an inequality in the methylation status and chromatin of the two Z chromosomes. We identified numerous MHM-related genomic and RNA sequences that possess a short conserved sequence common to the majority of clones, suggesting the functional importance of the MHM region. Some of the RNA sequences, which like MHM are expressed in females but not in males, are likely to be polyadenylated and have genomic intron/exon structure. The turkey, another galliform bird, has repetitive sequences in the predicted turkey MHM region, raising the question of regional dosage compensation in the turkey as in the chicken. Content Type Journal Article Category Research Article Pages 587-598 DOI 10.1007/s00412-011-0333-x Authors Yuichiro Itoh, Department of Integrative Biology and Physiology, University of California—Los Angeles, 610 Charles E. Young Drive South, Room 1146, Los Angeles, CA 90095-7239, USA Kathy Kampf, Department of Integrative Biology and Physiology, University of California—Los Angeles, 610 Charles E. Young Drive South, Room 1146, Los Angeles, CA 90095-7239, USA Arthur P. Arnold, Department of Integrative Biology and Physiology, University of California—Los Angeles, 610 Charles E. Young Drive South, Room 1146, Los Angeles, CA 90095-7239, USA Journal Chromosoma Online ISSN 1432-0886 Print ISSN 0009-5915 Journal Volume Volume 120 Journal Issue Volume 120, Number 6

Description:    Eukaryotic cells employ a plethora of conserved proteins and mechanisms to ensure genome integrity. In metazoa, these mechanisms must operate in the context of organism development. This mini-review highlights two emerging features of DNA damage responses in Drosophila : a crosstalk between DNA damage responses and components of the spindle assembly checkpoint, and increasing evidence for the effect of DNA damage on the developmental program at multiple points during the Drosophila life cycle. Content Type Journal Article Category Mini-Review Pages 547-555 DOI 10.1007/s00412-011-0342-9 Authors Tin Tin Su, MCD Biology, University of Colorado, Boulder, CO 80309-0347, USA Journal Chromosoma Online ISSN 1432-0886 Print ISSN 0009-5915 Journal Volume Volume 120 Journal Issue Volume 120, Number 6

Description:    Homologous chromosomes exchange genetic information through recombination during meiotic synapsis, a process that increases genetic diversity and is fundamental to sexual reproduction. Meiotic studies in mammalian species are scarce and mainly focused on human and mouse. Here, the meiotic recombination events were determined in three species of Platyrrhini monkeys ( Cebus libidinosus , Cebus nigritus and Alouatta caraya ) by analysing the distribution of MLH1 foci at the stage of pachytene. Moreover, the combination of immunofluorescence and fluorescent in situ hybridisation has enabled us to construct recombination maps of primate chromosomes that are homologous to human chromosomes 13 and 21. Our results show that (a) the overall number of MLH1 foci varies among all three species, (b) the presence of heterochromatin blocks does not have a major influence on the distribution of MLH1 foci and (c) the distribution of crossovers in the homologous chromosomes to human chromosomes 13 and 21 are conserved between species of the same genus ( C. libidinosus and C. nigritus ) but are significantly different between Cebus and Alouatta . This heterogeneity in recombination behaviour among Ceboidea species may reflect differences in genetic diversity and genome composition. Content Type Journal Article Category Research Article Pages 521-530 DOI 10.1007/s00412-011-0329-6 Authors Raquel Garcia-Cruz, Departament de Biologia Cellular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, UAB Campus, Bellaterra, 08193 Barcelona, Spain Sarai Pacheco, Departament de Biologia Cellular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, UAB Campus, Bellaterra, 08193 Barcelona, Spain Miguel Angel Brieño, Departament de Biologia Cellular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, UAB Campus, Bellaterra, 08193 Barcelona, Spain Eliana R. Steinberg, Grupo de Investigación en Biología Evolutiva (GIBE), CONICET, Departamento de Ecología, Genética y Evolución, FCEyN, Universidad de Buenos Aires, Buenos Aires, Argentina Marta D. Mudry, Grupo de Investigación en Biología Evolutiva (GIBE), CONICET, Departamento de Ecología, Genética y Evolución, FCEyN, Universidad de Buenos Aires, Buenos Aires, Argentina Aurora Ruiz-Herrera, Departament de Biologia Cellular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, UAB Campus, Bellaterra, 08193 Barcelona, Spain Montserrat Garcia-Caldés, Departament de Biologia Cellular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, UAB Campus, Bellaterra, 08193 Barcelona, Spain Journal Chromosoma Online ISSN 1432-0886 Print ISSN 0009-5915 Journal Volume Volume 120 Journal Issue Volume 120, Number 5

Description:    The dynamics of genome modification that occurred from the initial hybridization event to the stabilization of allopolyploid species remains largely unexplored. Here, we studied inheritance and expression of rDNA loci in the initial generations of Brassica napus allotetraploids (2 n  = 38, AACC) resynthesized from Brassica oleracea (2 n  = 18, CC) and B. rapa (2 n  = 20, AA) and compared the patterns to natural forms. Starting already from F1 generation, there was a strong uniparental silencing of B. oleracea genes. The epigenetic reprogramming was accompanied with immediate condensation of C-genome nucleolar organizer region (NOR) and progressive transgeneration hypermethylation of polymerase I promoters, mainly at CG sites. No such changes were observed in the A-genome NORs. Locus loss and gains affecting mainly non-NOR loci after the first allotetraploid meiosis did not influence established functional status of NORs. Collectively, epigenetic and genetic modifications in synthetic lines resemble events that accompanied formation of natural allopolyploid species. Content Type Journal Article Category Research Article Pages 557-571 DOI 10.1007/s00412-011-0331-z Authors Tomasz Książczyk, Institut National de la Recherche Agronomique (INRA), UMR118 APBV, BP 35327, 35653 Le Rheu cedex, France Ales Kovarik, Institute of Biophysics, Academy of Science of the Czech Republic, Brno, Czech Republic Frédérique Eber, Institut National de la Recherche Agronomique (INRA), UMR118 APBV, BP 35327, 35653 Le Rheu cedex, France Virginie Huteau, Institut National de la Recherche Agronomique (INRA), UMR118 APBV, BP 35327, 35653 Le Rheu cedex, France Lucie Khaitova, Institute of Biophysics, Academy of Science of the Czech Republic, Brno, Czech Republic Zuzana Tesarikova, Institute of Biophysics, Academy of Science of the Czech Republic, Brno, Czech Republic Olivier Coriton, Institut National de la Recherche Agronomique (INRA), UMR118 APBV, BP 35327, 35653 Le Rheu cedex, France Anne-Marie Chèvre, Institut National de la Recherche Agronomique (INRA), UMR118 APBV, BP 35327, 35653 Le Rheu cedex, France Journal Chromosoma Online ISSN 1432-0886 Print ISSN 0009-5915 Journal Volume Volume 120 Journal Issue Volume 120, Number 6

Description:    Sciara coprophila (Diptera, Nematocera) constitutes a classic model to analyze unusual chromosome behavior such as the somatic elimination of paternal X chromosomes, the elimination of the whole paternal, plus non-disjunction of the maternal X chromosome at male meiosis. The molecular organization of the heterochromatin in S. coprophila is mostly unknown except for the ribosomal DNA located in the X chromosome pericentromeric heterochromatin. The characterization of the centromeric regions, thus, is an essential and required step for the establishment of S. coprophila as a model system to study fundamental mechanisms of chromosome segregation. To accomplish such a study, heterochromatic sections of the X chromosome centromeric region from salivary glands polytene chromosomes were microdissected and microcloned. Here, we report the identification and characterization of two tandem repeated DNA sequences from the pericentromeric region of the X chromosome, a pericentromeric RTE element and an AT-rich centromeric satellite. These sequences will be important tools for the cloning of S. coprophila centromeric heterochromatin using libraries of large genomic clones. Content Type Journal Article Category Research Article Pages 387-397 DOI 10.1007/s00412-011-0320-2 Authors M. Carmen Escribá, Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Universidad Autónoma de Madrid, Nicolás Cabrera 1, 28049 Madrid, Spain Patricia G. Greciano, Departamento de Proliferación Celular y Desarrollo, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain María Méndez-Lago, Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Universidad Autónoma de Madrid, Nicolás Cabrera 1, 28049 Madrid, Spain Beatriz de Pablos, Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Universidad Autónoma de Madrid, Nicolás Cabrera 1, 28049 Madrid, Spain Vladimir A. Trifonov, Department of Veterinary Medicine, Cambridge Resource Centre for Comparative Genomics, Cambridge, UK Malcolm A. Ferguson-Smith, Department of Veterinary Medicine, Cambridge Resource Centre for Comparative Genomics, Cambridge, UK Clara Goday, Departamento de Proliferación Celular y Desarrollo, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain Alfredo Villasante, Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Universidad Autónoma de Madrid, Nicolás Cabrera 1, 28049 Madrid, Spain Journal Chromosoma Online ISSN 1432-0886 Print ISSN 0009-5915 Journal Volume Volume 120 Journal Issue Volume 120, Number 4

Description:    The chromodomain protein, Chromator, can be divided into two main domains, a NH 2 -terminal domain (NTD) containing the chromodomain (ChD) and a COOH-terminal domain (CTD) containing a nuclear localization signal. During interphase Chromator is localized to chromosomes; however, during cell division Chromator redistributes to form a macro molecular spindle matrix complex together with other nuclear proteins that contribute to microtubule spindle dynamics and proper chromosome segregation during mitosis. It has previously been demonstrated that the CTD is sufficient for targeting Chromator to the spindle matrix. In this study, we show that the NTD domain of Chromator is required for proper localization to chromatin during interphase and that chromosome morphology defects observed in Chromator hypomorphic mutant backgrounds can be largely rescued by expression of this domain. Furthermore, we show that the ChD domain can interact with histone H1 and that this interaction is necessary for correct chromatin targeting. Nonetheless, that localization to chromatin still occurs in the absence of the ChD indicates that Chromator possesses a second mechanism for chromatin association and we provide evidence that this association is mediated by other sequences residing in the NTD. Taken together these findings suggest that Chromator's chromatin functions are largely governed by the NH 2 -terminal domain whereas functions related to mitosis are mediated mainly by COOH-terminal sequences. Content Type Journal Article Category Research Article Pages 209-220 DOI 10.1007/s00412-011-0355-4 Authors Changfu Yao, Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, 3156, Molecular Biology Building, Ames, IA 50011, USA Yun Ding, Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, 3156, Molecular Biology Building, Ames, IA 50011, USA Weili Cai, Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, 3156, Molecular Biology Building, Ames, IA 50011, USA Chao Wang, Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, 3156, Molecular Biology Building, Ames, IA 50011, USA Jack Girton, Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, 3156, Molecular Biology Building, Ames, IA 50011, USA Kristen M. Johansen, Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, 3156, Molecular Biology Building, Ames, IA 50011, USA Jørgen Johansen, Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, 3156, Molecular Biology Building, Ames, IA 50011, USA Journal Chromosoma Online ISSN 1432-0886 Print ISSN 0009-5915 Journal Volume Volume 121 Journal Issue Volume 121, Number 2