Cloning and expression analysis of a potato cDNA that encodes branching enzyme: evidence for co-expression of starch biosynthetic genes.
One of the key enzymes involved in the formation of amylopectin, which is the major component of starch, is branching enzyme. A cDNA for potato branching enzyme was cloned by screening a tuber-specific cDNA expression library using an antiserum directed against a denatured preparation of the protein. Complementation of an Escherichia coli strain deficient in branching enzyme was achieved using a construct derived from this clone. Analysis of the expression of the gene in potato revealed a close association with conditions favouring starch biosynthesis. The expression pattern of the gene coding for potato branching enzyme, as analyzed at the mRNA level, closely resembles that of AGPase S, a gene coding for one of the subunits of ADP-glucose pyrophosphorylase, which is the key regulatory enzyme in the starch biosynthetic pathway. This raises the possibility that enzymes involved in the pathway are coordinately regulated at the transcriptional level.
Kossmann
J
J
Institut für Genbiologische Forschung, Berlin GmbH, Berlin, FRG.
Visser
R G
RG
Müller-Röber
B
B
Willmitzer
L
L
Sonnewald
U
U
D015061:1,4-alpha-Glucan Branching Enzyme / Q000235:genetics*; D000595:Amino Acid Sequence; D015152:Blotting, Northern; D050260:Carbohydrate Metabolism; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000378:metabolism; D015183:Restriction Mapping; D011198:Solanum tuberosum / Q000201:enzymology / Q000235:genetics*; D013213:Starch / Q000096:biosynthesis*
D012333:RNA, Messenger; D013213:Starch; D004247:DNA; D015061:1,4-alpha-Glucan Branching Enzyme