Assessment of procollagen processing defects by fibroblasts cultured in the presence of dextran sulphate.
The culture of skin fibroblasts in the presence of 0.01% (w/v) dextran sulphate results in complete proteolytic processing of procollagen to collagen. Processing occurs predominantly via a pN-collagen intermediate, suggesting that C-propeptide cleavage occurs early during the processing pathway. The processed collagen is associated with the cell-layer fraction. This method of inducing procollagen processing was evaluated for use in detecting procollagen processing abnormalities in heritable connective-tissue diseases. Abnormal type I procollagen processing was clearly demonstrated in two cases with known defects of pN-propeptide cleavage. In one, the cleavage deficiency was due to diminished N-proteinase activity (dermatosparaxis) and in the other case (Ehler's-Danlos syndrome type VIIA) the cleavage site was deleted. In a case of osteogenesis imperfecta (type II) the slow electrophoretic migration of type I collagen alpha-chains due to over-modification of lysine was readily demonstrated. Inefficient procollagen processing was also evident in this patient, as had been previously reported [de Wet, Pihlanjaniemi, Myers, Kelly & Prockop (1983) J. Biol. Chem. 258, 7721-7728]. Thus this method of culture in the presence of dextran sulphate provides a simple and rapid procedure for the detection of procollagen processing defects and electrophoretic abnormalities.
University of Melbourne, Department of Paediatrics, Royal Children's Hospital, Parkville, Vic., Australia.
J F
JF
Bateman
S B
SB
Golub
D000328:Adult; D002478:Cells, Cultured; D003094:Collagen / Q000096:biosynthesis; D003240:Connective Tissue Diseases / Q000378:metabolism; D016264:Dextran Sulfate; D003911:Dextrans / Q000494:pharmacology*; D010450:Endopeptidases / Q000502:physiology; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D011347:Procollagen / Q000378:metabolism*
D003911:Dextrans; D011347:Procollagen; D003094:Collagen; D016264:Dextran Sulfate; D010450:Endopeptidases