Type XIII collagen : organization and chromosomal localization of the mouse gene, distance between human COL13A1 and prolyl 4-hydroxylase α-subunit genes, and generation of mice expressing an N-terminally altered type XIII collagen
1University of Oulu, Faculty of Medicine, Department of Medical Biochemistry and Molecular Biology
|Online Access:||PDF Full Text (PDF, 1.3 MB)|
|Persistent link:|| http://urn.fi/urn:isbn:9514253949
Oulu : University of Oulu,
|Publish Date:|| 1999-09-27
|Thesis type:||Doctoral Dissertation
|Defence Note:||Academic Dissertation to be presented with the assent of the Faculty of Medicine, University of Oulu, for public discussion in the Auditorium of the Department of Medical Biochemistry, on December 2nd, 1999, at 12 noon.
Doctor Raija Soininen
Doctor Gerard Tromp
The complete exon-intron organization of the gene coding for the mouse α1(XIII) collagen chain, Col13a1, was characterized from genomic clones and multiple transcription initiation points were determined. Detailed comparison of the human and mouse genes showed that the exon-intron structures are completely conserved between the species, and both genes have their 5' untranslated region preceded by a highly conserved putative promoter region. The chromosomal location of the mouse gene was determined to be at chromosome 10, band B4, between markers D10Mit5 – (2.3 ± 1.6 cM) – Col13a1 – (3.4 ± 1.9 cM) – D10Mit15.
The location of the genes for both the catalytically important α-subunit of prolyl 4-hydroxylase (P4HA) and human type XIII collagen (COL13A1) were previously mapped to 10q21.3-23.1. Prolyl-4-hydroxylase catalyzes the formation of 4-hydroxyproline in collagens by the hydroxylation of peptide-bound proline and plays a crucial role in the synthesis of these proteins. The order and transcriptional orientation of the COL13A1 and P4HA was determined. These two genes were found to lie at tail to tail orientation on chromosome 10 and the distance between these genes was determined to be about 550 kbp.
To study the function of type XIII collagen we used gene targeting in ES cells to generate a mouse line that carries a mutated type XIII collagen gene. Instead of normal protein, mutant mice express type XIII collagen with an altered amino-terminus in which the cytosolic and the transmembrane domains have been replaced with an unrelated sequence. The homozygous mice are fertile and viable but they show alterations in skeletal muscles, mainly wavy sarcolemma and increased variation in muscle fiber diameter. Ultrastructural studies revealed additional abnormalities such as streaming of z-disks, accumulation and enlargement of mitochondria, and disorganized myofilaments. The basement membranes of the muscle cells showed areas of detachment from the plasma membrane and the fibrillar matrix of the cells was less compact than in control animals. Fibroblasts cultured from mutant mice had normal levels of type XIII collagen but exhibited decreased adhesion to substratum which might be explained by a reduced anchoring strength of the altered protein.
Acta Universitatis Ouluensis. D, Medica
© University of Oulu, 1999. This publication is copyrighted. You may download, display and print it for your own personal use. Commercial use is prohibited.