| First Author | Gieseg MA | Year | 1997 |
| Journal | Gen Comp Endocrinol | Volume | 108 |
| Issue | 2 | Pages | 199-208 |
| PubMed ID | 9356216 | Mgi Jnum | J:43997 |
| Mgi Id | MGI:1099248 | Doi | 10.1006/gcen.1997.6965 |
| Citation | Gieseg MA, et al. (1997) Elephantfish proinsulin possesses a monobasic processing site. Gen Comp Endocrinol 108(2):199-208 |
| abstractText | Total pancreatic RNA from the holocephalan species Callorhyncus milii (elephantfish) was used to make cDNA as a template for the polymerase chain reaction. Three redundant primers based on the known amino acid sequence of elephantfish insulin were used to amplify a fragment of proinsulin comprising truncated B-chain, complete C-peptide, and complete A-chain. Whereas the C-peptide/A-chain junction contained the expected dibasic cleavage site (-Lys-Arg-), the B-chain/C-peptide junction was found to contain only a single Arg, the first such site to be unequivocally associated with the proteolytic processing of a proinsulin to insulin. Examination of the flanking sequences around this site shows that a typical endocrine/neuroendocrine PC3 conversion enzyme should still be able to cleave, as the general requirements for precursor processing at a monobasic site are satisfied, notably a basic residue (Lys) at the -4 position. An acidic residue (in this case Asp) at the +1 position, which is seen in all known proinsulins, is maintained. The corresponding genomic DNA fragment of elephantfish proinsulin was also amplified by PCR, revealing a 402-bp intron at the conserved IVS-2 position within the C7 codon. Copyright 1997 Academic Press. Copyright 1997 Academic Press |
