DIFFERENT MOLECULAR-FORMS OF RAT-KIDNEY GP330, THE DOMINANT AUTOANTIGEN OF ACTIVE HEYMANN NEPHRITIS

The primary structure, consisting of 1650 amino acid residues, of the C-terminal end of the dominant autoantigen of active Heymann Nephritis , gp330, from rat kidney was obtained by cloning and sequencing of cDN A clones. Comparison of this sequence with the previously published se quences of fragments of the C-terminal end of gp330 [Raychowdhury, Nil es, McCluskey and Smith (1989) Science 244, 1163-1165] revealed certai n differences in their primary structures. These differences included several single amino acid substitutions, replacement of a stretch of 1 5 amino acid residues by a different stretch of six amino acid residue s, and different lengths of cytoplasmic domain (188 versus 213 amino a cid residues). These findings of two different primary structures of g p330 provide direct evidence for the existence of two molecular forms of gp330.