Characterization of a maize beta-amylase cDNA clone and its expression during seed germination.
A maize (Zea mays L.) cDNA clone (pZMB2) encoding beta-amylase was isolated from a cDNA library prepared from the aleurone RNA of germinating kernels. The cDNA encodes a predicted product of 488 amino acids with significant similarity to known beta-amylases from barley (Hordeum vulgare), rye (Secale cereale), and rice (Oryza sativa). Glycine-rich repeats found in the carboxyl terminus of the endosperm-specific beta-amylase of barley and rye are absent from the maize gene product. The N-terminal sequence of the first 20 amino acids of a beta-amylase peptide derived from purified protein is identical to the 5th through 24th amino acids of the predicted cDNA product, indicating the absence of a conventional signal peptide in the maize protein. Recombinant inbred mapping data indicate that the cDNA clone is single-copy gene that maps to chromosome 7L at position 83 centimorgans. Northern blot analysis and in vitro translation-immunoprecipitation data indicate that the maize beta-amylase is synthesized de novo in the aleurone cells but not in the scutellum during seed germination.
Wang
S M
SM
Department of Botany, National Taiwan University, Taipei.
Lue
W L
WL
Wu
S Y
SY
Huang
H W
HW
Chen
J
J
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D018628:Gene Dosage; D015870:Gene Expression; D017343:Genes, Plant; D018525:Germination; D008969:Molecular Sequence Data; D010802:Phylogeny; D021382:Protein Sorting Signals; D018749:RNA, Plant / Q000235:genetics; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D003313:Zea mays / Q000201:enzymology / Q000235:genetics*; D001614:beta-Amylase / Q000096:biosynthesis / Q000145:classification / Q000235:genetics*
D018076:DNA, Complementary; D021382:Protein Sorting Signals; D018749:RNA, Plant; D001614:beta-Amylase