Abstract
Two cDNA clones, pOS103 and pOS137, were isolated which code for distinct α-amylase isozymes in germinating rice seeds. Sequence analysis indicated that the clones encode polypeptides of approximately 48 kDa, both of which possess a signal peptide involved in directing secretion of the protein. Comparison of the two rice α-amylase amino acid sequence showed that they are 76% similar to each other, while showing 85% to 90% similarity with other cereal α-amylases. A comparison of eleven cereal α-amylases also revealed three new conserved regions (I′, II′, and IV′) not previously identified in the animal, bacterial, and fungal α-amylases. Regions I′ and IV′ are sites for intron splicing while region II' is probably involved in calcium binding. One of the rice a-amylase cDNAs, pOS103, encodes a protein that has two potential N-glycosylation sites, one in the signal peptide and the other in the mature portion of the protein. The cDNA clone, pOS137, encodes an α-amylase with a single glycosylation site in the signal peptide, suggesting that the mature OS137 isozyme is not glycosylated. Analysis of the expression of these genes in germinating rice seeds indicated that mRNA corresponding to pOS103 and pOS137 could be detected throughout a 48 h period of seed imbibition. RNA levels, however, were dramatically stimulated by treatment of embryoless half-seeds with exogenous GA3. Our results demonstrate that at least two forms of α-amylase are expressed in germinating rice seeds and that the expression of these genes is regulated by the phytohormone GA3.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 235-244 |
| Number of pages | 10 |
| Journal | MGG Molecular & General Genetics |
| Volume | 221 |
| Issue number | 2 |
| DOIs | |
| State | Published - Apr 1990 |
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Keywords
- DNA sequence
- Gibberellic acid
- Isozymes
- Protein structure
ASJC Scopus subject areas
- Genetics
Cite this
The α-amylase genes in Oryza sativa : Characterization of cDNA clones and mRNA expression during seed germination. / O'Neill, Sharman D.; Kumagai, Monto H.; Majumdar, Arindam; Huang, Ning; Sutliff, Thomas D.; Rodriguez, Raymond L.
In: MGG Molecular & General Genetics, Vol. 221, No. 2, 04.1990, p. 235-244.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The α-amylase genes in Oryza sativa
T2 - Characterization of cDNA clones and mRNA expression during seed germination
AU - O'Neill, Sharman D.
AU - Kumagai, Monto H.
AU - Majumdar, Arindam
AU - Huang, Ning
AU - Sutliff, Thomas D.
AU - Rodriguez, Raymond L.
PY - 1990/4
Y1 - 1990/4
N2 - Two cDNA clones, pOS103 and pOS137, were isolated which code for distinct α-amylase isozymes in germinating rice seeds. Sequence analysis indicated that the clones encode polypeptides of approximately 48 kDa, both of which possess a signal peptide involved in directing secretion of the protein. Comparison of the two rice α-amylase amino acid sequence showed that they are 76% similar to each other, while showing 85% to 90% similarity with other cereal α-amylases. A comparison of eleven cereal α-amylases also revealed three new conserved regions (I′, II′, and IV′) not previously identified in the animal, bacterial, and fungal α-amylases. Regions I′ and IV′ are sites for intron splicing while region II' is probably involved in calcium binding. One of the rice a-amylase cDNAs, pOS103, encodes a protein that has two potential N-glycosylation sites, one in the signal peptide and the other in the mature portion of the protein. The cDNA clone, pOS137, encodes an α-amylase with a single glycosylation site in the signal peptide, suggesting that the mature OS137 isozyme is not glycosylated. Analysis of the expression of these genes in germinating rice seeds indicated that mRNA corresponding to pOS103 and pOS137 could be detected throughout a 48 h period of seed imbibition. RNA levels, however, were dramatically stimulated by treatment of embryoless half-seeds with exogenous GA3. Our results demonstrate that at least two forms of α-amylase are expressed in germinating rice seeds and that the expression of these genes is regulated by the phytohormone GA3.
AB - Two cDNA clones, pOS103 and pOS137, were isolated which code for distinct α-amylase isozymes in germinating rice seeds. Sequence analysis indicated that the clones encode polypeptides of approximately 48 kDa, both of which possess a signal peptide involved in directing secretion of the protein. Comparison of the two rice α-amylase amino acid sequence showed that they are 76% similar to each other, while showing 85% to 90% similarity with other cereal α-amylases. A comparison of eleven cereal α-amylases also revealed three new conserved regions (I′, II′, and IV′) not previously identified in the animal, bacterial, and fungal α-amylases. Regions I′ and IV′ are sites for intron splicing while region II' is probably involved in calcium binding. One of the rice a-amylase cDNAs, pOS103, encodes a protein that has two potential N-glycosylation sites, one in the signal peptide and the other in the mature portion of the protein. The cDNA clone, pOS137, encodes an α-amylase with a single glycosylation site in the signal peptide, suggesting that the mature OS137 isozyme is not glycosylated. Analysis of the expression of these genes in germinating rice seeds indicated that mRNA corresponding to pOS103 and pOS137 could be detected throughout a 48 h period of seed imbibition. RNA levels, however, were dramatically stimulated by treatment of embryoless half-seeds with exogenous GA3. Our results demonstrate that at least two forms of α-amylase are expressed in germinating rice seeds and that the expression of these genes is regulated by the phytohormone GA3.
KW - DNA sequence
KW - Gibberellic acid
KW - Isozymes
KW - Protein structure
UR - http://www.scopus.com/inward/record.url?scp=0025363754&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0025363754&partnerID=8YFLogxK
U2 - 10.1007/BF00261726
DO - 10.1007/BF00261726
M3 - Article
C2 - 2370848
AN - SCOPUS:0025363754
VL - 221
SP - 235
EP - 244
JO - Molecular Genetics and Genomics
JF - Molecular Genetics and Genomics
SN - 1617-4615
IS - 2
ER -