References of "Imai, K"
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See detailComparative analysis of the genomic organization of Pax9 and its conserved physical association with Nkx2-9 in the human, mouse, and pufferfish genomes.
Santagati, F.; Gerber, J. K.; Blusch, J. H. et al

in Mammalian Genome : Official Journal of the International Mammalian Genome Society (2001), 12(3), 232-7

As a first step towards the identification of cis-regulatory elements of Pax9 by means of comparative genomics, we have analyzed genome regions encompassing the Pax9 gene in three vertebrate species ... [more ▼]

As a first step towards the identification of cis-regulatory elements of Pax9 by means of comparative genomics, we have analyzed genome regions encompassing the Pax9 gene in three vertebrate species, humans, mice (Mus musculus), and the Japanese pufferfish (Fugu rubripes). We show the genomic organization of Pax9 and its physical association with Nkx2-9 conserved in the three species. We discuss about possible implications of the conserved synteny between Pax9 and Nkx2-9 in a context of vertebrate evolution. This report also includes the first description of the primary structures of Fugu Pax9 and Nkx2-9. Furthermore, we report the identification of a novel upstream exon and putative transcription start sites in mouse Pax9. Our results suggest that transcription of Pax9 may be initiated at two alternative start sites and driven by TATA-less promoters. [less ▲]

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See detailZic1 regulates the patterning of vertebral arches in cooperation with Gli3.
Aruga, J.; Mizugishi, K.; Koseki, H. et al

in Mechanisms of Development (1999), 89(1-2), 141-50

Skeletal abnormalities are described that appeared in Zic1-deficient mice. These mice show multiple abnormalities in the axial skeleton. The deformities are severe in the dorsal parts of the vertebrae ... [more ▼]

Skeletal abnormalities are described that appeared in Zic1-deficient mice. These mice show multiple abnormalities in the axial skeleton. The deformities are severe in the dorsal parts of the vertebrae, vertebral arches, but less so in the vertebral bodies (spina bifida occulta). The proximal ribs are deformed having ectopic processes. The abnormalities found in the vertebral arches can be traced back to disturbed segmental patterns of dorsal sclerotome. The Zic1/Gli3 double mutants showed severe abnormalities of vertebral arches not found in single mutants. The abnormalities in the vertebral arches were less severe in Zic1/Pax1 mutants than Zic1/Gli3 mutants, but significantly more pronounced than in Zic1 single mutants. The three genes may act synergistically in the development of the vertebral arches. [less ▲]

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See detailPax1 and Pax9 synergistically regulate vertebral column development.
Peters, H.; Wilm, B.; Sakai, N. et al

in Development (1999), 126(23), 5399-408

The paralogous genes Pax1 and Pax9 constitute one group within the vertebrate Pax gene family. They encode closely related transcription factors and are expressed in similar patterns during mouse ... [more ▼]

The paralogous genes Pax1 and Pax9 constitute one group within the vertebrate Pax gene family. They encode closely related transcription factors and are expressed in similar patterns during mouse embryogenesis, suggesting that Pax1 and Pax9 act in similar developmental pathways. We have recently shown that mice homozygous for a defined Pax1 null allele exhibit morphological abnormalities of the axial skeleton, which is not affected in homozygous Pax9 mutants. To investigate a potential interaction of the two genes, we analysed Pax1/Pax9 double mutant mice. These mutants completely lack the medial derivatives of the sclerotomes, the vertebral bodies, intervertebral discs and the proximal parts of the ribs. This phenotype is much more severe than that of Pax1 single homozygous mutants. In contrast, the neural arches, which are derived from the lateral regions of the sclerotomes, are formed. The analysis of Pax9 expression in compound mutants indicates that both spatial expansion and upregulation of Pax9 expression account for its compensatory function during sclerotome development in the absence of Pax1. In Pax1/Pax9 double homozygous mutants, formation and anteroposterior polarity of sclerotomes, as well as induction of a chondrocyte-specific cell lineage, appear normal. However, instead of a segmental arrangement of vertebrae and intervertebral disc anlagen, a loose mesenchyme surrounding the notochord is formed. The gradual loss of Sox9 and Collagen II expression in this mesenchyme indicates that the sclerotomes are prevented from undergoing chondrogenesis. The first detectable defect is a low rate of cell proliferation in the ventromedial regions of the sclerotomes after sclerotome formation but before mesenchymal condensation normally occurs. At later stages, an increased number of cells undergoing apoptosis further reduces the area normally forming vertebrae and intervertebral discs. Our results reveal functional redundancy between Pax1 and Pax9 during vertebral column development and identify an early role of Pax1 and Pax9 in the control of cell proliferation during early sclerotome development. In addition, our data indicate that the development of medial and lateral elements of vertebrae is regulated by distinct genetic pathways. [less ▲]

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See detailNotochord-dependent expression of MFH1 and PAX1 cooperates to maintain the proliferation of sclerotome cells during the vertebral column development.
Furumoto, T. A.; Miura, N.; Akasaka, T. et al

in Developmental Biology (1999), 210(1), 15-29

During axial skeleton development, the notochord is essential for the induction of the sclerotome and for the subsequent differentiation of cartilage forming the vertebral bodies and intervertebral discs ... [more ▼]

During axial skeleton development, the notochord is essential for the induction of the sclerotome and for the subsequent differentiation of cartilage forming the vertebral bodies and intervertebral discs. These functions are mainly mediated by the diffusible signaling molecule Sonic hedgehog. The products of the paired-box-containing Pax1 and the mesenchyme forkhead-1 (Mfh1) genes are expressed in the developing sclerotome and are essential for the normal development of the vertebral column. Here, we demonstrate that Mfh1 like Pax1 expression is dependent on Sonic hedgehog signals from the notochord, and Mfh1 and Pax1 act synergistically to generate the vertebral column. In Mfh1/Pax1 double mutants, dorsomedial structures of the vertebrae are missing, resulting in extreme spina bifida accompanied by subcutaneous myelomeningocoele, and the vertebral bodies and intervertebral discs are missing. The morphological defects in Mfh1/Pax1 double mutants strongly correlate with the reduction of the mitotic rate of sclerotome cells. Thus, both the Mfh1 and the Pax1 gene products cooperate to mediate Sonic hedgehog-dependent proliferation of sclerotome cells. [less ▲]

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See detailTargeted disruption of Pax1 defines its null phenotype and proves haploinsufficiency.
Wilm, B.; Dahl, E.; Peters, H. et al

in Proceedings of the National Academy of Sciences of the United States of America (1998), 95(15), 8692-7

The murine paired box-containing gene Pax1 is required for normal development of the vertebral column, the sternum, and the scapula. Previous studies have shown that three natural Pax1 mouse mutants, the ... [more ▼]

The murine paired box-containing gene Pax1 is required for normal development of the vertebral column, the sternum, and the scapula. Previous studies have shown that three natural Pax1 mouse mutants, the undulated alleles, exhibit phenotypes of different severity in these skeletal elements. Nevertheless, these analyses have not clarified whether the semidominant Undulated short-tail (Uns) mutation, in which the complete Pax1 locus is deleted, represents a null allele. Moreover, the analyses of the classical undulated mutants did not allow a conclusion with respect to haploinsufficiency of Pax1. To address both questions we have created a Pax1 null allele in mice by gene targeting. Surprisingly, the phenotype of this defined mutation exhibits clear differences to that of Uns. This result strongly indicates the contribution of additional gene(s) to the Uns mutant phenotype. Furthermore, the phenotype of mice heterozygous for the null allele demonstrates that Pax1 is haploinsufficient in some though not all skeletal elements which express Pax1 during embryonic development. [less ▲]

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See detailPax genes and skeletal development.
Balling, Rudi UL; Helwig, U.; Nadeau, J. et al

in Annals of the New York Academy of Sciences (1996), 785

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See detailInteraction between undulated and Patch leads to an extreme form of spina bifida in double-mutant mice.
Helwig, U.; Imai, K.; Schmahl, W. et al

in Nature Genetics (1995), 11(1), 60-3

The aetiology of spina bifida involves genetic and environmental factors, which may be why major genes contributing to pathogenesis have not been identified. Here we report that undulated-Patch double ... [more ▼]

The aetiology of spina bifida involves genetic and environmental factors, which may be why major genes contributing to pathogenesis have not been identified. Here we report that undulated-Patch double-mutant mice have a phenotype reminiscent of an extreme form of spina bifida occulta in humans. This unexpected phenotype in double-mutant but not single-mutant mice shows that novel congenital anomalies such as spina bifida can result from interaction between products of independently segregating loci. This example of digenic inheritance may explain the often sporadic nature of spina bifida in humans. [less ▲]

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See detailThe genetic map around the tail kinks (tk) locus on mouse chromosome 9.
Imai, K.; Nass, S. J.; Olowson, M. et al

in Mammalian Genome : Official Journal of the International Mammalian Genome Society (1993), 4(10), 560-4

Tail kinks (tk) is a classical mouse skeletal mutation, located on Chromosome (Chr) 9. As the first step for the positional cloning of the tk gene, we have established a genetic map of a region ... [more ▼]

Tail kinks (tk) is a classical mouse skeletal mutation, located on Chromosome (Chr) 9. As the first step for the positional cloning of the tk gene, we have established a genetic map of a region surrounding the tk locus by generating a backcross segregating for tk. From this backcross, 1004 progeny were analyzed for the coat-color phenotype of the proximally located dilute (d) gene and for the distally flanking microsatellite marker, D9Mit12. Fifty-six recombinants between d and tk and 75 recombinants between tk and D9Mit12 were identified, completing a panel of 130 recombinants including one double recombinant. This panel allowed us to map five microsatellite loci as well as d and Mod-1 with respect to tk. We show that one of the microsatellite markers mapped, D9Mit9, does not recombine at all with tk in our backcross. This indicates that the D9Mit9 locus will serve as a good starting point for a chromosomal walk to the tk gene. [less ▲]

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See detailThe genetics of skeletal development.
Balling, Rudi UL; Ebensperger, C.; Hoffmann, I. et al

in Annales de Génétique (1993), 36(1), 56-62

A genetic analysis of biologic processes has provided substantial advances in developmental biology. Whereas the genetic analysis of Drosophila is a potent system, recently developed tools have enabled a ... [more ▼]

A genetic analysis of biologic processes has provided substantial advances in developmental biology. Whereas the genetic analysis of Drosophila is a potent system, recently developed tools have enabled a genetic analysis of the development of vertebrates. For these studies, numerous mouse mutants are available and many more will be introduced in the near future. Mutations involving the skeleton are easy to detect. This article reports the phenotype and molecular analysis of two mutant mouse strains with skeletal abnormalities, undulated (un) and Danforth's short tail (Sd). The role of the corresponding genes in skeletal development of these two mutants and the basis for their genetic interaction are discussed. [less ▲]

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See detailMapping of the Mod-1 locus on mouse chromosome 9.
Nass, S. J.; Olowson, M.; Miyashita, N. et al

in Mammalian Genome : Official Journal of the International Mammalian Genome Society (1993), 4(6), 333-7

A new method for typing the Mod-1 locus on mouse Chromosome (Chr) 9 was developed, based on restriction fragment length polymorphism (RFLP) within a polymerase chain reaction (PCR)-amplified fragment. The ... [more ▼]

A new method for typing the Mod-1 locus on mouse Chromosome (Chr) 9 was developed, based on restriction fragment length polymorphism (RFLP) within a polymerase chain reaction (PCR)-amplified fragment. The new method led us to revise the strain distribution pattern (SDP) of Mod-1 in the BXD (C57BL/6J x DBA/2J) and AKXD (AKR/J x DBA/2J) recombinant inbred (RI) strains. The new SDP eliminates several previously reported examples of double recombination events between Mod-1 and the closest flanking loci in the BXD and AKXD strains. In the BXD strains, the revised SDP of Mod-1 was identical to that of the Mod-1-related D9Rtil locus. Thus, the identity of D9Rtil as a Mod-1-related locus rather than Mod-1 itself is in question. The method was also applied to an interspecific backcross panel between an inbred strain of Mus musculus molossinus (MSM/Ms) and C57BL/6J to map Mod-1 with respect to surrounding microsatellite loci, defining the proximal localization of Mod-1 with respect to D9Mit10 with a genetic distance of 0.6 +/- 0.6 cM. [less ▲]

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See detailA new Pax gene, Pax-9, maps to mouse chromosome 12.
Wallin, J.; Mizutani, Y.; Imai, K. et al

in Mammalian Genome : Official Journal of the International Mammalian Genome Society (1993), 4(7), 354-8

Members of the Pax gene family have recently been shown to play important roles in mouse embryogenesis. Of eight so far characterized Pax genes, three have been associated with mouse developmental mutants ... [more ▼]

Members of the Pax gene family have recently been shown to play important roles in mouse embryogenesis. Of eight so far characterized Pax genes, three have been associated with mouse developmental mutants. Here we report the cloning of a new Pax gene, Pax-9. Most of the DNA sequence encoding the highly conserved paired domain has been determined and compared with previously known paired domains. This comparison classifies Pax-9 as a member of the same subgroup as Pax-1/undulated. By analysis of the segregation of a Pax-9 restriction fragment length polymorphism and a large number of simple sequence length polymorphisms in an interspecific C57BL/6 x Mus musculus mollosinus backcross, Pax-9 was mapped close to the D12Nds1 locus on the proximal part of Chromosome (Chr) 12. [less ▲]

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