| 1. |
- Braun, Attila, et al.
(författare)
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Genomic organization of profilin-III and evidence for a transcript expressed exclusively in testis.
- 2002
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Ingår i: Gene. - 1879-0038. ; 283:1-2, s. 219-225
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Tidskriftsartikel (refereegranskat)abstract
- Profilins are small, widely expressed actin binding proteins, thought to be key regulators of actin dynamics in living cells. So far, three profilin-genes have been described: profilin-I (PFN1), profilin-II (PFN2) with two splice variants and the recently identified profilin-III (PFN3). Here we describe the genomic organization of the genes encoding human and mouse profilin-III. Both are single exon genes and lie in close vicinity to the renal sodium-phosphate transport gene 2 (SLC34A1, NPT2) which is highly expressed in kidney. Northern hybridization to rat tissues has previously demonstrated expression of an approximately 4.5 kb long profilin-III mRNA transcript in kidney and a mRNA transcript of approximately 1 kb in length in testis. Here we show that mouse profilin-III expression is restricted to testis and that the 4.2 kb profilin-III mRNA in kidney is the result of a slc34a1 transcript which includes the antisense profilin-III open reading frame in its 3prime prime or minute-untranslated region. Finally, we demonstrate by in situ hybridization that profilin-III mRNA is localized to cells in the late stage of spermatogenesis.
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| 2. |
- Brandau, Oliver, et al.
(författare)
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Chondromodulin I Is Dispensable during Enchondral Ossification and Eye Development.
- 2002
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Ingår i: Molecular and Cellular Biology. - 0270-7306. ; 22:18, s. 6627-6635
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Tidskriftsartikel (refereegranskat)abstract
- Chondromodulin I (chm-I), a type II transmembrane protein, is highly expressed in the avascular zones of cartilage but is downregulated in the hypertrophic region, which is invaded by blood vessels during enchondral ossification. In vitro and in vivo assays with the purified protein have shown chondrocyte-modulating and angiogenesis-inhibiting functions. To investigate chm-I function in vivo, we generated transgenic mice lacking chm-I mRNA and protein. Null mice are viable and fertile and show no morphological changes. No abnormalities in vascular invasion and cartilage development were detectable. No evidence was found for a compensating function of tendin, a recently published homologue highly expressed in tendons and also, at low levels, in cartilage. Furthermore, no differences in the expression of other angiogenic or antiangiogenic factors such as transforming growth factor beta1 (TGF-beta1), TGF-beta2, TGF-beta3, fibroblast growth factor 2, and vascular endothelial growth factor were found. The surprising lack of phenotype in the chm-I-deficient mice suggests either a different function for chm-I in vivo than has been proposed or compensatory changes in uninvestigated angiogenic or angiogenesis-inhibiting factors. Further analysis using double-knockout technology will be necessary to analyze the function of chm-I in the complex process of enchondral ossification.
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| 3. |
- Costell, Mercedes, et al.
(författare)
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Perlecan maintains the integrity of cartilage and some basement membranes
- 1999
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Ingår i: Journal of Cell Biology. - 0021-9525. ; 147:5, s. 1109-1122
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Tidskriftsartikel (refereegranskat)abstract
- Perlecan is a heparan sulfate proteoglycan that is expressed in all basement membranes (BMs), in cartilage, and several other mesenchymal tissues during development. Perlecan binds growth factors and interacts with various extracellular matrix proteins and cell adhesion molecules. Homozygous mice with a null mutation in the perlecan gene exhibit normal formation of BMs. However, BMs deteriorate in regions with increased mechanical stress such as the contracting myocardium and the expanding brain vesicles showing that perlecan is crucial for maintaining BM integrity. As a consequence, small clefts are formed in the cardiac muscle leading to blood leakage into the pericardial cavity and an arrest of heart function. The defects in the BM separating the brain from the adjacent mesenchyme caused invasion of brain tissue into the overlaying ectoderm leading to abnormal expansion of neuroepithelium, neuronal ectopias, and exencephaly. Finally, homozygotes developed a severe defect in cartilage, a tissue that lacks BMs. The chondrodysplasia is characterized by a reduction of the fibrillar collagen network, shortened collagen fibers, and elevated expression of cartilage extracellular matrix genes, suggesting that perlecan protects cartilage extracellular matrix from degradation.
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| 4. |
- Empere, Marta, et al.
(författare)
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Aggrecan governs intervertebral discs development by providing critical mechanical cues of the extracellular matrix
- 2023
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Ingår i: Frontiers in Bioengineering and Biotechnology. - : Frontiers Media SA. - 2296-4185. ; 11, s. 1-19
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Tidskriftsartikel (refereegranskat)abstract
- Aggrecan (ACAN) is localized in the intervertebral disc (IVD) in unique compartment-specific patterns where it contributes to the tissue structure and mechanical function together with collagens. The extracellular matrix (ECM) of the IVD undergoes degenerative changes during aging, misuse or trauma, which inevitably alter the biochemical and biomechanical properties of the tissue. A deeper understanding of these processes can be achieved in genetically engineered mouse models, taking into account the multifaceted aspects of IVD development. In this study, we generated aggrecan insertion mutant mice (AcaniE5/iE5) by interrupting exon 5 coding for the G1 domain of ACAN, and analyzed the morphological and mechanical properties of the different IVD compartments during embryonic development. Western blotting using an antibody against the total core protein failed to detect ACAN in cartilage extracts, whereas immunohistochemistry by a G1-specific antibody showed weak signals in vertebral tissues of AcaniE5/iE5 mice. Homozygous mutant mice are perinatally lethal and characterized by short snout, cleft palate and disproportionate dwarfism. Whole-mount skeletal staining and µ-CT analysis of AcaniE5/iE5 mice at embryonic day 18.5 revealed compressed vertebral bodies with accelerated mineralization compared to wild type controls. In AcaniE5/iE5 mice, histochemical staining revealed collapsed extracellular matrix with negligible sulfated glycosaminoglycan content accompanied by a high cellular density. Collagen type II deposition was not impaired in the IVD of AcaniE5/iE5 mice, as shown by immunohistochemistry. Mutant mice developed a severe IVD phenotype with deformed nucleus pulposus and thinned cartilaginous endplates accompanied by a disrupted growth plate structure in the vertebral body. Atomic force microscopy (AFM) imaging demonstrated a denser collagen network with thinner fibrils in the mutant IVD zones compared to wild type. Nanoscale AFM indentation revealed bimodal stiffness distribution attributable to the softer proteoglycan moiety and harder collagenous fibrils of the wild type IVD ECM. In AcaniE5/iE5 mice, loss of aggrecan resulted in a marked shift of the Young’s modulus to higher values in all IVD zones. In conclusion, we demonstrated that aggrecan is pivotal for the determination and maintenance of the proper stiffness of IVD and vertebral tissues, which in turn could play an essential role in providing developmental biomechanical cues.
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| 5. |
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| 6. |
- Hedlund, Petter, et al.
(författare)
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Erectile dysfunction in cyclic GMP-dependent kinase I-deficient mice.
- 2000
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 97:5, s. 2349-2354
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Tidskriftsartikel (refereegranskat)abstract
- The generation of nitric oxide (NO) in penile erectile tissue and the subsequent elevation of cyclic GMP (cGMP) levels are important for normal penile erection. Current treatments of erectile dysfunction elevate either cGMP levels by blocking cGMP degrading phosphodiesterase 5 or cyclic AMP (cAMP) levels by intrapenile injection of prostaglandin E1. The molecular target or targets of cGMP in erectile tissue and the role of cAMP for normal penile erection are not known. Herein, we report that mice lacking cGMP-dependent kinase I (cGKI) have a very low ability to reproduce and that their corpora cavernosa fail to relax on activation of the NO/cGMP signaling cascade. Elevation of cAMP by forskolin, however, induces similar relaxation in normal and cGKI-null corpus cavernosum. In addition, sperm derived from cGKI-null mice is normal, can undergo acrosomal reactions, and can efficiently fertilize eggs. Altogether, these data identify cGKI as the downstream target of cGMP in erectile tissue and provide evidence that cAMP signaling cannot compensate for the absence of the cGMP/cGKI signaling cascade in vivo.
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| 7. |
- Kvist, Alexander, et al.
(författare)
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Chondroitin sulfate perlecan enhances collagen fibril formation - Implications for perlecan chondrodysplasias
- 2006
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 281:44, s. 33127-33139
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Tidskriftsartikel (refereegranskat)abstract
- Inactivation of the perlecan gene leads to perinatal lethal chondrodysplasia. The similarity to the phenotypes of the Col2A1 knock-out and the disproportionate micromelia mutation suggests perlecan involvement in cartilage collagen matrix assembly. We now present a mechanism for the defect in collagen type II fibril assembly by perlecan-null chondrocytes. Cartilage perlecan is a heparin sulfate or a mixed heparan sulfate/ chondroitin sulfate proteoglycan. The latter form binds collagen and accelerates fibril formation in vitro, with more defined fibril morphology and increased fibril diameters produced in the presence of perlecan. Interestingly, the enhancement of collagen fibril formation is independent on the core protein and is mimicked by chondroitin sulfate E but neither by chondroitin sulfate D nor dextran sulfate. Furthermore, perlecan chondroitin sulfate contains the 4,6-disulfated disaccharides typical for chondroitin sulfate E. Indeed, purified glycosaminoglycans from perlecan-enriched fractions of cartilage extracts contain elevated levels of 4,6-disulfated chondroitin sulfate disaccharides and enhance collagen fibril formation. The effect on collagen assembly is proportional to the content of the 4,6- disulfated disaccharide in the different cartilage extracts, with growth plate cartilage glycosaminoglycan being the most efficient enhancer. These findings demonstrate a role for perlecan chondroitin sulfate side chains in cartilage extracellular matrix assembly and provide an explanation for the perlecan-null chondrodysplasia.
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| 8. |
- Mates, L, et al.
(författare)
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Comparative analysis of the mouse and human genes (Matn2 and MATN2) for matrilin-2, a filament-forming protein widely distributed in extracellular matrices
- 2002
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Ingår i: Matrix Biology. - 1569-1802. ; 21:2, s. 163-174
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Tidskriftsartikel (refereegranskat)abstract
- We previously identified matrilin-2 (MATN2), the largest member of the novel family of matrilins. These filament-forming adapter proteins expressed in a distinct, but partially overlapping, pattern in all tissues were implicated in the organization of the extracellular matrix. Matrilin-2 functions in a great variety of tissues. Here, we present the genomic organization of the highly conserved mouse and human MATN2 loci, which cover > 100 kb and 167.167 kb genomic regions, respectively, and are composed of 19 exons. RT-PCR analysis revealed that alternative transcripts with identical protein coding regions are transcribed from two promoters in both species. The upstream, housekeeping type promoter is functional in all tissues and cell types tested. The activity of the downstream, TATA-like promoter preceded with putative motifs for the homeobox transcription factor PRRX2 is restricted to embryonic fibroblasts and certain cell lines. The oligomerization module is split by an U12-type AT-AC intron found in conserved position in all four matrilin genes. We assigned Matn2 to mouse chromosome 15, linked to Trhr and Sntb1 in a region synthenic to human chromosome 8q22-24.
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| 9. |
- Popova, Svetlana N., et al.
(författare)
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alpha 11 beta 1 integrin-dependent regulation of periodontal ligament function in the erupting mouse incisor
- 2007
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Ingår i: Molecular and Cellular Biology. - 0270-7306 .- 1098-5549. ; 27:12, s. 4306-4316
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Tidskriftsartikel (refereegranskat)abstract
- The fibroblast integrin alpha 11 beta 1 is a key receptor for fibrillar collagens. To study the potential function of alpha 11. in vivo, we generated a null allele of the alpha 11 gene. Integrin alpha 1(-/-) mice are viable and fertile but display dwarfism with increased mortality, most probably due to severely defective incisors. Mutant incisors are characterized by disorganized periodontal ligaments, whereas molar ligaments appear normal. The primary defect in the incisor ligament leads to halted tooth eruption. alpha 11 beta 1-defective embryonic fibroblasts displayed severe defects in vitro, characterized by (i) greatly reduced cell adhesion and spreading on collagen 1, (ii) reduced ability to retract collagen lattices, and (iii) reduced cell proliferation. Analysis of matrix metalloproteinase in vitro and in vivo revealed disturbed MMP13 and MMP14 synthesis in alpha 11(-/-) cells. We show that alpha 11 beta 1 is the major receptor for collagen I on mouse embryonic fibroblasts and suggest that alpha 11 beta 1 integrin is specifically required on periodontal ligament fibroblasts for cell migration and collagen reorganization to help generate the forces needed for axial tooth movement. Our data show a unique role for alpha 11 beta 1 integrin during tooth eruption.
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| 10. |
- Sasse, Philipp, et al.
(författare)
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Perlecan is critical for heart stability
- 2008
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Ingår i: Cardiovascular Research. - : Oxford University Press (OUP). - 1755-3245 .- 0008-6363. ; 80:3, s. 435-444
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Tidskriftsartikel (refereegranskat)abstract
- Perlecan is a heparansulfate proteoglycan found in basement membranes, cartilage, and several mesenchymal tissues that form during development, tumour growth, and tissue repair. Loss-of-function mutations in the perlecan gene in mice are associated with embryonic lethality caused primarily by cardiac abnormalities probably due to hemopericards. The aim of the present study was to investigate the mechanism underlying the early embryonic lethality and the pathophysiological relevance of perlecan for heart function. Perlecan-deficient murine embryonic stem cells were used to investigate the myofibrillar network and the electrophysiological properties of single cardiomyocytes. The mechanical stability of the developing perlecan-deficient mouse hearts was analysed by microinjecting fluorescent-labelled dextran. Maturation and formation of basement membranes and cell-cell contacts were investigated by electron microscopy, immunohistochemistry, and western blotting. Sarcomere formation and cellular functional properties were unaffected in perlecan-deficient cardiomyocytes. However, the intraventricular dye injection experiments revealed mechanical instability of the early embryonic mouse heart muscle wall before embryonic day 10.5 (E10.5). Accordingly, perlecan-null embryonic hearts contained lower amounts of the critical basement membrane components, collagen IV and laminins. Furthermore, basement membranes were absent in perlecan-null cardiomoycytes whereas adherens junctions formed and matured around E9.5. Infarcted hearts from perlecan heterozygous mice displayed reduced heart function when compared with wild-type hearts. We propose that perlecan plays an important role in maintaining the integrity during cardiac development and is important for heart function in the adult heart after injury.
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| 11. |
- Svensson, Liz, et al.
(författare)
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Cartilage oligomeric matrix protein-deficient mice have normal skeletal development.
- 2002
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Ingår i: Molecular and Cellular Biology. - 0270-7306. ; 22:12, s. 4366-4371
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Tidskriftsartikel (refereegranskat)abstract
- Cartilage oligomeric matrix protein (COMP) belongs to the thrombospondin family and is a homopentamer primarily expressed in cartilage. Mutations in the COMP gene result in the autosomal dominant chondrodysplasias pseudoachondroplasia (PSACH) and some types of multiple epiphyseal dysplasia (MED), which are characterized by mild to severe short-limb dwarfism and early-onset osteoarthritis. We have generated COMP-null mice to study the role of COMP in vivo. These mice show no anatomical, histological, or ultrastructural abnormalities and show none of the clinical signs of PSACH or MED. Northern blot analysis and immunohistochemical analysis of cartilage indicate that the lack of COMP is not compensated for by any other member of the thrombospondin family. The results also show that the phenotype in PSACH/MED cartilage disorders is not caused by the reduced amount of COMP.
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