SECRETION OF RECOMBINANT RAT ANNEXIN-5 BY INSECT CELLS IN A BACULOVIRUS EXPRESSION SYSTEM

Rat annexin 5 was expressed in insect cells using a baculovirus vector , Autographa californica nuclear polyhedrosis virus. The rat annexin 5 cDNA was prepared by a polymerase chain reaction using mRNA from rat pituitary glands and placed under the control of the polyhedrin promot er. The gene product was 36 k dalton acid was recognized by anti-rat a nnexin 5 serum. The calcium dependent binding of the recombinant annex in 5 to membranes was confirmed. The recombinant protein appeared in t he medium by 21 hours post-inoculation in high amount and this was spe cific to this recombinant virus. High potassium milieu (20 mM KCl) for two hours increased the release of the recombinant protein but not fo r the recombinant beta-galactosidase prepared for a control. These res ults reveal that the product of the annexin 5 gene, which lacks a sign al sequence, follows a secretory pathway in insect cells. (C) 1994 Aca demic Press, Inc.