The relationship of ASE-1 and NOR-90 in autoimmune sera.
OBJECTIVE
The nucleolar proteins ASE-1 and NOR-90 can become confused because they have similar cytological and Western blot features. We investigated the frequency and relationship between these 2 proteins and identified clinical features of patients with ASE-1 antibodies.


METHODS
The characteristics of ASE-1 and NOR-90 are shown by indirect immunofluorescence (IIF) and Western blot data. The sera are characterized by their ability to immunoprecipitate the in vitro transcription and translation (TnT) product of either the ASE-1 or NOR-90 cDNA. Clinical features were obtained by retrospective chart review.


RESULTS
Of the 15 sera identified as potentially NOR-90 positive by IIF and Western blot 8/15 (53%) were able to immunoprecipitate a NOR-90 TnT product. Of the remaining 7 sera, 4 (57%) were only able to immunoprecipitate an ASE-1 TnT product. Four (57%) of the remaining 7 sera were able to immunoprecipitate an ASE-1 TnT product. In a second cohort of confirmed NOR-90 positive sera, 2/8 (25%) were able to immunoprecipitate an ASE-1 TnT product. In total, ASE-1 autoantibodies were found in 6/16 (37.5%) of confirmed NOR-90 sera from both cohorts. There were no common clinical features found in seven ASE-1 positive patients; however, 3 (43%) had a malignancy and 3 (43%) had slowly progressive systemic sclerosis.


CONCLUSIONS
Autoantibodies to ASE-1 and NOR-90 can occur alone or together in autoimmune sera. Due to their similar IIF and Western blot profile the only way to correctly characterize these sera is by immunoprecipitation of the appropriate TnT product.
Whitehead
C M
CM
Department of Medical Biochemistry, University of Calgary, Alberta, Canada.
Fritzler
M J
MJ
Rattner
J B
JB
D001323:Autoantibodies / Q000032:analysis; D001324:Autoantigens / Q000032:analysis* / Q000276:immunology; D015153:Blotting, Western; D002352:Carrier Proteins; D015331:Cohort Studies; D004268:DNA-Binding Proteins / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007106:Immune Sera / Q000276:immunology*; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D035463:Pol1 Transcription Initiation Complex Proteins; D011233:Precipitin Tests; D014176:Protein Biosynthesis / Q000502:physiology; D012318:RNA Polymerase I; D014157:Transcription Factors / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D014158:Transcription, Genetic / Q000502:physiology
D001323:Autoantibodies; D001324:Autoantigens; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D007106:Immune Sera; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D035463:Pol1 Transcription Initiation Complex Proteins; D014157:Transcription Factors; C063844:transcription factor UBF; C119975:POLR1G protein, human; D012318:RNA Polymerase I