STA11, a Chlamydomonas reinhardtii locus required for normal starch granule biogenesis, encodes disproportionating enzyme. Further evidence for a function of alpha-1,4 glucanotransferases during starch granule biosynthesis in green algae.
In Chlamydomonas reinhardtii, the presence of a defective STA11 locus results in significantly reduced granular starch deposition displaying major modifications in shape and structure. This defect simultaneously leads to the accumulation of linear malto-oligosaccharides (MOS). The mutants of STA11 were showed to lack D-enzyme, a plant alpha-1,4 glucanotransferase analogous to the Escherichia coli amylomaltase. We have cloned and characterized both the cDNA and gDNA corresponding to the C. reinhardtii D-enzyme. We now report allele-specific modifications of the D-enzyme gene in the mutants of STA11. These allele-specific modifications cosegregate with the corresponding sta11 mutations, thereby demonstrating that STA11 encodes D-enzyme. MOS production and starch accumulation were investigated during day and night cycles in wild-type and mutant C. reinhardtii cells. We demonstrate that in the algae MOS are produced during starch biosynthesis and degraded during the phases of net polysaccharide catabolism.
Wattebled
Fabrice
F
Unité de Glycobiologie Structurale et Fonctionnelle, Université des Sciences et Technologies de Lille, 59655 Villeneuve D'Ascq cedex, France.
Ral
Jean-Philippe
JP
Dauvillée
David
D
Myers
Alan M
AM
James
Martha G
MG
Schlichting
Ralf
R
Giersch
Christoph
C
Ball
Steven G
SG
D'Hulst
Christophe
C
D020418:Algal Proteins / Q000235:genetics / Q000378:metabolism; D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D016825:Chlamydomonas reinhardtii / Q000201:enzymology / Q000235:genetics*; D003001:Cloning, Molecular; D004247:DNA / Q000737:chemistry / Q000235:genetics; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D006004:Glycogen Debranching Enzyme System / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D009844:Oligosaccharides / Q000378:metabolism; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013213:Starch / Q000096:biosynthesis* / Q000378:metabolism
D020418:Algal Proteins; D018076:DNA, Complementary; D006004:Glycogen Debranching Enzyme System; D009844:Oligosaccharides; D012333:RNA, Messenger; C021705:maltooligosaccharides; D013213:Starch; D004247:DNA; C020569:4 alpha-glucanotransferase