title: Messenger RNA from isolated aleurone cells directs the synthesis of an alpha-galactosidase found in the endosperm during germination of guar (Cyamopsis tetragonaloba) seed.
abstract: In cereals and some legumes the aleurone layer is a site of synthesis of enzymes which mobilize endosperm reserves. It has been established whether or not the aleurone cells of the seed endosperm of Cyamopsis tetragonaloba are a site of synthesis of α-galactosidase. The isolation and cultivation of aleurone cells demonstrated that they contain mRNA which directs the synthesis and secretion of α-galactosidase into the endosperm where along with a β-mannanase it is responsible for the degradation of the galactomannan storage polymer. A method was developed to purify the mRNA from the aleurone cells of germinating seeds. This mRNA was analysed by: i) Northern blot hybridization using oligo-nucleotide mixed probes derived from the protein's NH2-terminal amino acid sequence and ii) in vitro translation in a wheat germ system and detection of the α-galactosidase protein using antibodies. The molecular mass of the protein synthesized in vitro is slightly larger (44 kDa) than that of the mature α-galactosidase (40.5 kDa) which is as expected for the precursor of a secreted protein.
authors.affiliation: Unilever Research Laboratory Colworth House, Sharnbrook, United Kingdom.
authors.forename: S G
authors.initials: SG
authors.lastname: Hughes
authors.forename: N
authors.initials: N
authors.lastname: Overbeeke
authors.forename: S
authors.initials: S
authors.lastname: Robinson
authors.forename: K
authors.initials: K
authors.lastname: Pollock
authors.forename: F L
authors.initials: FL
authors.lastname: Smeets