Osteogenesis imperfecta is a clinically heterogeneous disorder that affects more than 1/20,000 individuals. The phenotypic range is from lethal in the perinatal period, to a mild increase in fracture frequency. More than 90% of affected individuals have mutations in the genes that encode the chains of type I collagen, the major structural protein of bone. The objectives of studies proposed in this application are to determine how these mutations perturb molecular assembly, intracellular transport, secretion, and extracellular processing and; to identify the mechanisms by which, and the intracellular locations at which, cells recognize abnormal proteins and initiate strategies to prevent their secretion. The yeast two-hybrid system will be used to identify novel proteins that interact with portions of the type I procollagen molecule, and those genes isolated and characterized. Antibodies to the newly identified proteins, as well as antibodies to type I procollagen, HSP47, GRP78 and GRP94, and prolyl-hydroxylase (PDI) will be used to determine which proteins interact with the abnormal molecules synthesized by cells from patients with different classes of mutations in the COLIAI and COLIA2 genes. Additional mutations will be identified that occur at CpG sites in the regions that encode glycine residues in the triple helix of both chains of type I procollagen, by analysis with restriction endonucleases of those known sites (36 in the COLIAI gene and 27 in the COLIA2). Further additional mutations that occur in large families with variable expression, and those for which a parent is mosaic, will be sought to elucidate the basis for variable expression. Finally, the kinetics of MRNA processing for mutations that affect splicing will be identified. These studies are intended to increase the ability to understand the phenotypic effects of mutations, and identify sites along the processing pathway where intervention could ameliorate the phenotypic effects of mutations in collagen genes.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR041223-08
Application #
6043200
Study Section
Orthopedics and Musculoskeletal Study Section (ORTH)
Program Officer
Sharrock, William J
Project Start
1992-01-05
Project End
2001-09-29
Budget Start
1999-08-01
Budget End
2001-09-29
Support Year
8
Fiscal Year
1999
Total Cost
Indirect Cost
Name
University of Washington
Department
Pathology
Type
Schools of Medicine
DUNS #
135646524
City
Seattle
State
WA
Country
United States
Zip Code
98195
Pace, James M; Wiese, Mary; Drenguis, Andrea S et al. (2008) Defective C-propeptides of the proalpha2(I) chain of type I procollagen impede molecular assembly and result in osteogenesis imperfecta. J Biol Chem 283:16061-7
Morello, Roy; Bertin, Terry K; Chen, Yuqing et al. (2006) CRTAP is required for prolyl 3- hydroxylation and mutations cause recessive osteogenesis imperfecta. Cell 127:291-304
Persikov, Anton V; Pillitteri, Rian J; Amin, Priyal et al. (2004) Stability related bias in residues replacing glycines within the collagen triple helix (Gly-Xaa-Yaa) in inherited connective tissue disorders. Hum Mutat 24:330-7
Schwarze, Ulrike; Hata, Ryu-Ichiro; McKusick, Victor A et al. (2004) Rare autosomal recessive cardiac valvular form of Ehlers-Danlos syndrome results from mutations in the COL1A2 gene that activate the nonsense-mediated RNA decay pathway. Am J Hum Genet 74:917-30
Pace, James M; Corrado, Marcella; Missero, Caterina et al. (2003) Identification, characterization and expression analysis of a new fibrillar collagen gene, COL27A1. Matrix Biol 22:3-14
Johnson, M T; Morrison, S; Heeger, S et al. (2002) A variant of osteogenesis imperfecta type IV with resolving kyphomelia is caused by a novel COL1A2 mutation. J Med Genet 39:128-32
Marlowe, A; Pepin, M G; Byers, P H (2002) Testing for osteogenesis imperfecta in cases of suspected non-accidental injury. J Med Genet 39:382-6
Pace, J M; Kuslich, C D; Willing, M C et al. (2001) Disruption of one intra-chain disulphide bond in the carboxyl-terminal propeptide of the proalpha1(I) chain of type I procollagen permits slow assembly and secretion of overmodified, but stable procollagen trimers and results in mild osteogenesis imperfec J Med Genet 38:443-9
Byers, P H (2001) Folding defects in fibrillar collagens. Philos Trans R Soc Lond B Biol Sci 356:151-7; discussion 157-8
Bateman, J F; Freddi, S; Lamande, S R et al. (1999) Reliable and sensitive detection of premature termination mutations using a protein truncation test designed to overcome problems of nonsense-mediated mRNA instability. Hum Mutat 13:311-7

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