COORDINATED EXPRESSION AND ACTIVITY OF 3-HYDROXY-3-METHYLGLUTARYL COENZYME-A SYNTHASE AND REDUCTASE IN THE FAT-BODY OF BLATTELLA-GERMANICA (L) DURING VITELLOGENESIS

Levels of mRNA for the two 3-hydroxy-3-methylglutaryl coenzyme A (HMG- CoA) synthases, (HMG-S1 and HMG-S2), and for HMG-CoA reductase (HMG-R) of Blattella germanica were analyzed in the fat body during the first gonadotrophic cycle, HMG-S2 and HMG-R showed the highest mRNA levels on day 0 and decreased thereafter, whereas HMG-S1, showed faint expres sion, Western blot using specific antibodies for HMG-S1 and HMG-S2 sho wed no detectable levels for HMG-S1 but a clear pattern for HMG-SZ Bot h results point to a very limited role for HMG-CoA synthase-l in B. ge rmanica: fat body and suggest that the functional enzyme in this organ is HMG-CoA synthase-2 HMG-CoA reductase and synthase proteins shared a cyclic pattern (maximum levels at day 4 and minimum levels on days 0 and 8), which was coincident with the pattern of activity, The delay between gene transcription and protein synthesis suggests a finely reg ulated translation mechanism, Moreover, the pattern of mevalonate synt hesis parallels that of vitellogenin production, suggesting a coordina te mechanism between the mevalonate pathway and the production of vite llogenin. Copyright (C) 1996 Published by Elsevier Science Ltd