Sense and antisense RNA for the membrane associated 40 kDa subunit M40 of the insect V-ATPase

For the first time a cDNA encoding the membrane associated subunit M40 of an invertebrate V-ATPase has been isolated and sequenced, based on a cDNA library from larval midgut of the tobacco hornworm, Manduca sexta, Immunoblotting with monospecific antibodies raised against the recombinant M40 polypeptide demonstrated that it is a subunit of the insect plasma membrane V-ATPase, Since M40 subunits had been identified only in endosomal V-ATPases till now, this result indicates that they are constitutive members of all, endomembrane and plasma membrane V-ATPases, A phagemid clone representing a polyadenylated antisense transcript was also isolated and sequenced, Using RT-PCR, endogenous antisense RNA was detected in poly(A) RNA isolated from the larval midgut, Since Southern blots indicated a single gene locus, both the antisense RNA as well as the sense mRNA encoding subunit M40 seem to originate from the same gene. (C) 1997 Federation of European Biochemical Societies.