title: Identification of target mRNAs for the clock-controlled RNA-binding protein Chlamy 1 from Chlamydomonas reinhardtii.
abstract: An endogenous clock regulates the temporal expression of genes/mRNAs that are involved in the circadian output pathway. In the green alga Chlamydomonas reinhardtii, a clock-controlled RNA-binding protein (Chlamy 1) was identified recently, which represents an analog of the circadian trans-acting factor CCTR from the phylogenetically diverse alga Gonyaulax polyedra. In order to identify in C. reinhardtii target mRNAs that can be recognized by Chlamy 1, gel mobility-shift assays and UV-crosslinking experiments were carried out, and revealed that this protein interacts specifically with the 3' untranslated regions of several mRNAs and recognizes them all via a common cis-acting element, composed of at least seven UG repeats. By using competition assays, it was found that the affinity of Chlamy 1 is highest for mRNAs whose products are key components of nitrogen and CO2 metabolism. Since the activities of enzymes involved in nitrogen metabolism vary in a temporal pattern that is opposite in phase to that of Chlamy 1 binding activity, the protein may repress the translation of the cognate mRNAs.
authors.affiliation: Botanisches Institut, Ludwig-Maximilians-Universität München, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Waltenberger
authors.forename: C
authors.initials: C
authors.lastname: Schneid
authors.forename: J O
authors.initials: JO
authors.lastname: Grosch
authors.forename: A
authors.initials: A
authors.lastname: Bareiss
authors.forename: M
authors.initials: M
authors.lastname: Mittag
mesh_terms: D020413:3' Untranslated Regions; D000818:Animals; D001683:Biological Clocks / Q000502:physiology*; D002245:Carbon Dioxide / Q000378:metabolism; D016825:Chlamydomonas reinhardtii / Q000378:metabolism*; D002940:Circadian Rhythm / Q000502:physiology; D009584:Nitrogen / Q000378:metabolism; D011485:Protein Binding; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D012091:Repetitive Sequences, Nucleic Acid
chemical_list: D020413:3' Untranslated Regions; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D002245:Carbon Dioxide; D009584:Nitrogen