Molecular cloning of the complementary DNA for an additional member of the family of aortic aneurysm antigenic proteins.
OBJECTIVE
We have purified and partially sequenced a protein from the adventitia of the human aorta (aortic aneurysm antigenic protein 40 kDa; AAAP-40) that has homologies to bovine aortic microfibril-associated glycoprotein (MAGP-36). It is immunoreactive with immunoglobulin G (IgGs) purified from the serum and aortic wall of patients with abdominal aortic aneurysms. AAAP-40 and MAGP-36 have fibrinogen-like and vitronectin-like motifs. Screening an expression library constructed from human aortic adventitial messenger RNA has resulted in the cloning of three complementary DNAs whose gene products are immunoreactive with immunoglobulin G from patients with abdominal aortic aneurysms. Two strongly resemble each other and have been described separately. The purpose of this article is to report the third clone.


METHODS
Messenger RNA from a specimen of human aortic aneurysmal adventitia was reverse-transcribed for insertion into the phagemid Uni Zap XR (Stratagene). A strain of Escherichia coli, engineered for expression (XL 1-Blue MFR', Stratagene), was transfected, and rabbit antihuman vitronectin antibody as used to identify positive clones. Sequencing of the positive clones was performed by the Core Laboratories at Columbia University.


RESULTS
The hypothetical protein of rAAAP-CL4 (clone 4) shares sequence motifs with known microfibril-associated glycoproteins (MAGPs). The recombinant protein (rAAAP-CL4) is immunoreactive with serum from patients (three of four abdominal aortic aneurysm sera). In addition, similarities have been detected with immunoglobulins of the kappa family and with a protein from cytomegalovirus that is a potential molecular mimic.


CONCLUSIONS
There may several members of a novel family of human aortic autoantigenic proteins implicated in abdominal aortic aneurysm disease.
Hirose
H
H
Columbia University, New York, NY, USA.
Ozsvath
K J
KJ
Xia
S
S
Tilson
M D
MD
D000595:Amino Acid Sequence; D017544:Aortic Aneurysm, Abdominal / Q000235:genetics*; D003001:Cloning, Molecular; D003285:Contractile Proteins / Q000235:genetics*; D018076:DNA, Complementary / Q000737:chemistry* / Q000235:genetics; D004547:Elastic Tissue / Q000378:metabolism*; D016326:Extracellular Matrix Proteins; D005786:Gene Expression Regulation; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D008969:Molecular Sequence Data; D000072260:RNA Splicing Factors; D012333:RNA, Messenger / Q000235:genetics; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic
D003285:Contractile Proteins; D018076:DNA, Complementary; D016326:Extracellular Matrix Proteins; D007074:Immunoglobulin G; D000072260:RNA Splicing Factors; D012333:RNA, Messenger; C016598:microfibrillar protein