Antibody raised to AKAAAKAAAKA sequence on tropoelastin recognizes tropoelastin but not mature crosslinked elastin: A new tool in metabolic and structural studies of elastogenesis
B. Starcher et al., Antibody raised to AKAAAKAAAKA sequence on tropoelastin recognizes tropoelastin but not mature crosslinked elastin: A new tool in metabolic and structural studies of elastogenesis, CONNECT TIS, 40(4), 1999, pp. 273
Tropoelastin, which is secreted from the cell in a soluble form, contains s
pecific alanine rich repeat domains that are destined to form covalent desm
osine and isodesmosine crosslinks in mature insoluble elastin. We raised a
monospecific polyclonal antibody to a AKAAAKAAAKA synthetic peptide (AKA) w
hich represents this alanine rich region of tropoelastin. The antibody was
reactive with the original peptide antigen and purified tropoelastin, but n
ot with mature crosslinked elastin isolated from several animal species. Co
nditioned media from chick aorta smooth muscle cells in culture reacted in
an ELISA with the AKA antibody, but only in the presence of BAPN to block t
he conversion of the epsilon-amino groups to aldehydes, Immunofluorescence
demonstrated that the AKA antibody decorated newly deposited tropoelastin a
ssembled in fine fibrils in matrix produced by cultured human skin fibrobla
sts, EM-immunogold specifically localized this antibody to the immature ela
stic fibers present in fetal sheep ductus arteriosus. Moreover, immunohisto
chemistry demonstrated that the antibody recognized nonpolymerized tropoela
stin assembled on the periphery of elastic fibers in the aorta of chicks ra
ised on copper deficient and BAPN containing diets. These studies demonstra
te that this new anti-tropoelastin antibody can be used as a useful tool to
investigate elastin metabolism where it is important to distinguish betwee
n tropoelastin and mature crosslinked elastin.