title: Circadian synthesis of a nuclear-encoded chloroplast glyceraldehyde-3-phosphate dehydrogenase in the dinoflagellate Gonyaulax polyedra is translationally controlled.
abstract: The circadian clock has previously been shown to restrict synthesis of several proteins in the dinoflagellate Gonyaulax polyedra to only a few hours each day. We have identified one of these proteins as glyceraldehyde-3-phosphate dehydrogenase. Two nuclear genes encoding the enzyme have been cloned, one corresponding to a cytoplasmic isoform and the other to a plastid targeted protein. On the basis of protein microsequence data, we conclude that the synthesis of the plastid isoform is clock-regulated. This regulation is not related to mRNA levels, which remain constant throughout the cycle, suggesting a translational control mechanism, in contrast to the transcriptional regulation of GAPDH that has been demonstrated in Neurospora. Although the rhythm of synthesis has a high amplitude, the abundance and activity rhythms are greatly attenuated, which is attributed to the long half-life of the protein.
authors.affiliation: Department of Molecular & Cellular Biology, Harvard University, Cambridge, Massachusetts 02138-2020, USA.
authors.forename: T
authors.initials: T
authors.lastname: Fagan
authors.forename: D
authors.initials: D
authors.lastname: Morse
authors.forename: J W
authors.initials: JW
authors.lastname: Hastings
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D002736:Chloroplasts / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D002940:Circadian Rhythm / Q000235:genetics; D003001:Cloning, Molecular; D004141:Dinoflagellida / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D015180:Electrophoresis, Gel, Two-Dimensional; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000096:biosynthesis* / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D007527:Isoenzymes / Q000096:biosynthesis / Q000302:isolation & purification / Q000502:physiology; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009243:NAD / Q000378:metabolism; D014176:Protein Biosynthesis / Q000502:physiology
chemical_list: D007527:Isoenzymes; D009243:NAD; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases