Overgrowth of a Mouse Model of the Simpson–Golabi–Behmel Syndrome Is Independent of IGF Signaling
The type 1 Simpson–Golabi–Behmel overgrowth syndrome (SGBS1) is caused by loss-of-function mutations of the X-linked GPC3 gene encoding glypican-3, a cell-surface heparan sulfate proteoglycan that apparently plays a negative role in growth control by an unknown mechanism. Mice carrying a Gpc3 gene k...
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| Published in: | Developmental biology Vol. 243; no. 1; pp. 185 - 206 |
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| Main Authors: | , , , , , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
United States
Elsevier Inc
01.03.2002
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| Subjects: | |
| ISSN: | 0012-1606, 1095-564X |
| Online Access: | Get full text |
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| Summary: | The type 1 Simpson–Golabi–Behmel overgrowth syndrome (SGBS1) is caused by loss-of-function mutations of the X-linked GPC3 gene encoding glypican-3, a cell-surface heparan sulfate proteoglycan that apparently plays a negative role in growth control by an unknown mechanism. Mice carrying a Gpc3 gene knockout exhibited several phenotypic features that resemble clinical hallmarks of SGBS1, including somatic overgrowth, renal dysplasia, accessory spleens, polydactyly, and placentomegaly. In Gpc3/ΔH19 double mutants (lacking GPC3 and also carrying a deletion around the H19 gene region that causes bialellic expression of the closely linked Igf2 gene by imprint relaxation), the Gpc3-null phenotype was exacerbated, while additional SGBS1 features (omphalocele and skeletal defects) were manifested. However, results from a detailed comparative analysis of growth patterns in double mutants lacking GPC3 and also IGF2, IGF1, or the type 1 IGF receptor (IGF1R) provided conclusive genetic evidence inconsistent with the hypothesis that GPC3 acts as a growth suppressor by sequestering or downregulating an IGF ligand. Nevertheless, our data are compatible with a model positing that there is downstream convergence of the independent signaling pathways in which either IGFs or (indirectly) GPC3 participate. |
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| Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2 |
| ISSN: | 0012-1606 1095-564X |
| DOI: | 10.1006/dbio.2001.0554 |