References of "Wallin, J"
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See detailThe Genetics of Vertebral Column Development
Peters, H; Neubüser, A; Wallin, J et al

in Thiel; Klug (Eds.) Methods in Developmental Toxicology (1997)

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See detailPax1 is expressed during development of the thymus epithelium and is required for normal T-cell maturation.
Wallin, J.; Eibel, H.; Neubuser, A. et al

in Development (1996), 122(1), 23-30

Pax1 is a transcriptional regulatory protein expressed during mouse embryogenesis and has been shown to have an important function in vertebral column development. Expression of Pax1 mRNA in the embryonic ... [more ▼]

Pax1 is a transcriptional regulatory protein expressed during mouse embryogenesis and has been shown to have an important function in vertebral column development. Expression of Pax1 mRNA in the embryonic thymus has been reported previously. Here we show that Pax1 protein expression in thymic epithelial cells can be detected throughout thymic development and in the adult. Expression starts in the early endodermal epithelium lining the foregut region and includes the epithelium of the third pharyngeal pouch, a structure giving rise to part of the thymus epithelium. In early stages of thymus development a large proportion of thymus cells expresses Pax1. With increasing age, the proportion of Pax1-expressing cells is reduced and in the adult mouse only a small fraction of cortical thymic stromal cells retains strong Pax1 expression. Expression of Pax1 in thymus epithelium is necessary for establishing the thymus microenvironment required for normal T cell maturation. Mutations in the Pax-1 gene in undulated mice affect not only the total size of the thymus but also the maturation of thymocytes. The number of thymocytes is reduced about 2- to 5-fold, affecting mainly the CD4+8+ immature and CD4+ mature thymocyte subsets. The expression levels of major thymocyte surface markers remains unchanged with the exception of Thy-1 which was found to be expressed at 3- to 4-fold higher levels. [less ▲]

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See detailThe role of Pax-1 in axial skeleton development.
Wallin, J.; Wilting, J.; Koseki, H. et al

in Development (1994), 120(5), 1109-21

Previous studies have identified a single amino-acid substitution in the transcriptional regulator Pax-1 as the cause of the mouse skeletal mutant undulated (un). To evaluate the role of Pax-1 in the ... [more ▼]

Previous studies have identified a single amino-acid substitution in the transcriptional regulator Pax-1 as the cause of the mouse skeletal mutant undulated (un). To evaluate the role of Pax-1 in the formation of the axial skeleton we have studied Pax-1 protein expression in early sclerotome cells and during subsequent embryonic development, and we have characterized the phenotype of three different Pax-1 mouse mutants, un, undulated-extensive (unex) and Undulated short-tail (Uns). In the Uns mutation the whole Pax-1 locus is deleted, resulting in the complete absence of Pax-1 protein in these mice. The other two genotypes are interpreted as hypomorphs. We conclude that Pax-1 is necessary for normal vertebral column formation along the entire axis, although the severity of the phenotype is strongest in the lumbar region and the tail. Pax-1-deficient mice lack vertebral bodies and intervertebral discs. The proximal part of the ribs and the rib homologues are also missing or severely malformed, whereas neural arches are nearly normal. Pax-1 is thus required for the development of the ventral parts of vertebrae. Embryonic analyses reveal that although sclerotomes are formed in mutant embryos, abnormalities can be detected from day 10.5 p.c. onwards. The phenotypic analyses also suggest that the notochord still influences vertebral body formation some days after the sclerotomes are formed. Furthermore, the notochord diameter is larger in mutant embryos from day 12 p.c., due to increased cell proliferation. In the strongly affected genotypes the notochord persists as a rod-like structure and the nucleus pulposus is never properly formed. Since the notochord is Pax-1-negative these findings suggest a bidirectional interaction between notochord and paraxial mesoderm. The availability of these Pax-1 mutant alleles permitted us to define an early role for Pax-1 in sclerotome patterning as well as a late role in intervertebral disc development. Our observations suggest that Pax-1 function is required for essential steps in ventral sclerotome differentiation, i.e. for the transition from the mesenchymal stage to the onset of chondrogenesis. [less ▲]

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See detailExpression and function of Pax 1 during development of the pectoral girdle.
Timmons, P. M.; Wallin, J.; Rigby, P. W. et al

in Development (1994), 120(10), 2773-85

Pax 1 is a member of the paired-box containing gene family. Expression has previously been observed in the developing sclerotomes and later in the anlagen of the intervertebral discs. Analysis of Pax 1 ... [more ▼]

Pax 1 is a member of the paired-box containing gene family. Expression has previously been observed in the developing sclerotomes and later in the anlagen of the intervertebral discs. Analysis of Pax 1-deficient undulated mice revealed an important role for this gene in the development of the axial skeleton, in which Pax 1 apparently functions as a mediator of notochordal signals during sclerotome differentiation. Here we demonstrate that Pax 1 is also transiently expressed in the developing limb buds. A comparative phenotypic analysis of different undulated alleles shows that this expression is of functional significance. In mice that are mutant for the Pax 1 gene severe developmental abnormalities are found in the pectoral girdle. These include fusions of skeletal elements which would normally remain separate, and failures in the differentiation of blastemas into cartilaginous structures. Although Pax 1 is also expressed in the developing hindlimb buds and Wolffian ridge, no malformations could be detected in the corresponding regions of Pax 1 mutant mice. These findings show that, in addition to its role in the developing vertebral column, Pax 1 has an important function in the development of parts of the appendicular skeleton. [less ▲]

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See detailMouse genetics and the development of vertebral column development
Balling, Rudi UL; Koseki, H; Wallin, J et al

in Proceedings Greenwood Genetics Center (1994), (13), 58-60

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See detailA role for Pax-1 as a mediator of notochordal signals during the dorsoventral specification of vertebrae.
Koseki, H.; Wallin, J.; Wilting, J. et al

in Development (1993), 119(3), 649-60

The notochord plays an important role in the differentiation of the paraxial mesoderm and the neural tube. We have analyzed the role of the notochord in somite differentiation and subsequent formation of ... [more ▼]

The notochord plays an important role in the differentiation of the paraxial mesoderm and the neural tube. We have analyzed the role of the notochord in somite differentiation and subsequent formation of the vertebral column using a mouse mutant, Danforth's short-tail (Sd). In this mutant, the skeletal phenotype is most probably a result of degeneration and subsequent loss of the notochord. The Sd gene is known to interact with undulated (un), a sclerotome mutant. Double mutants between Sd and un alleles show an increase in the severity of the defects, mainly in the ventral parts of the vertebrae. We also show that part of the Sd phenotype is strikingly similar to that of the un alleles. As un is known to be caused by a mutation in the Pax-1 gene, we analyzed Pax-1 expression in Sd embryos. In Sd embryos, Pax-1 expression is reduced, providing a potential molecular basis for the genetic interaction observed. A complete loss of Pax-1 expression in morphologically intact mesenchyme was found in the lower thoracic-lumbar region, which is phenotypically very similar to the corresponding region in a Pax-1 null mutant, Undulated short-tail. The sclerotome developmental abnormalities in Sd coincide closely, both in time and space, with notochordal changes, as determined by whole-mount T antibody staining. These findings indicate that an intact notochord is necessary for normal Pax-1 expression in sclerotome cells, which is in turn required for the formation of the ventral parts of the vertebrae. The observed correlation among structural changes of the notochord, Pax-1 expression levels and skeletal phenotypes, suggests that Pax-1 might be an intrinsic mediator of notochordal signals during the dorsoventral specification of vertebrae. [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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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 detailDevelopment of the skeletal system.
Balling, Rudi UL; Lau, C. F.; Dietrich, S. et al

in Ciba Foundation Symposium (1992), 165

The analysis of the development of the skeletal system has been greatly facilitated by the availability of a large number of mouse mutants with skeletal defects. Whereas for many of these mutants a ... [more ▼]

The analysis of the development of the skeletal system has been greatly facilitated by the availability of a large number of mouse mutants with skeletal defects. Whereas for many of these mutants a description of the main phenotypic abnormalities is known, molecular insight into the ontogeny of the skeletal system is limited. One of the few skeletal mutants for which the molecular basis is known is undulated. These mice have a defect in the differentiation of the sclerotome and Pax-1, a mouse paired-box containing gene, has been identified as a candidate gene for this mutation. A molecular analysis of three independent undulated alleles revealed that in each case the Pax-1 gene is affected. One of the alleles could be classified as a null allele, in which the Pax-1 gene is deleted. A phenotypic analysis shows that Pax-1 is required for proper differentiation of intervertebral discs and vertebral bodies. [less ▲]

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