Synthesis and differentially regulated processing of proinsulin in developing chick pancreas, liver and neuroretina.
Regulated preproinsulin gene expression in nonpancreatic tissues during development has been demonstrated in rodents, Xenopus and chicken. Little is known, however, about the synthesis and processing of the primary protein product, proinsulin, in comparison with these events in pancreas. Using specific antisera and immunocytochemistry, immunoblot and HPLC criteria, we characterize the differential processing of proinsulin in developing neuroretina, liver and pancreas. The chick embryo pancreas expresses the convertase PC2, and largely processes proinsulin to insulin. In contrast, little or no mature PC2 is present in embryonic liver and neuroretina and the (pro)insulin immunoactivity identified is predominantly proinsulin.
Alarcón
C
C
Department of Cellular and Developmental Biology, Centro de Investigaciones Biológicas, C.S.I.C., Madrid, Spain.
Serna
J
J
Pérez-Villamil
B
B
de Pablo
F
F
D000818:Animals; D002642:Chick Embryo; D018507:Gene Expression Regulation, Developmental; D007328:Insulin; D007515:Islets of Langerhans / Q000196:embryology* / Q000378:metabolism; D008099:Liver / Q000196:embryology* / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D009924:Organ Culture Techniques; D011384:Proinsulin / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism*; D011498:Protein Precursors / Q000235:genetics* / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D012160:Retina / Q000166:cytology / Q000196:embryology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014981:Xenopus
D007328:Insulin; D011498:Protein Precursors; C013737:preproinsulin; D011384:Proinsulin