title: Photoperiod-regulated expression of the PpCOL1 gene encoding a homolog of CO/COL proteins in the moss Physcomitrella patens.
abstract: The CONSTANS (CO) protein is a critical regulator of the photoperiodic control of flowering in Arabidopsis thaliana and Oryza sativa. We isolated a cDNA PpCOL1 encoding a homolog of the CO/CO-LIKE (COL) family proteins from a cryptogam Physcomitrella patens. The predicted PpCOL1 protein has N-terminal zinc finger and C-terminal CCT domains, which are conserved in the angiosperm CO/COL proteins. Structurally, PpCOL1 is the most closely related to the Group Ia or Ic proteins, which include AtCO and AtCOL1/2, among diverged members of the family. A transient expression assay using GFP showed that the CCT domain of PpCOL1 contains a nuclear-localizing signal. Northern blotting analyses revealed that the PpCOL1 expression is controlled by the circadian clock, and moreover, it is photoperiodically regulated at a gametophore stage when the rate of sporophyte formation is affected by day length. These observations indicate a possible involvement of PpCOL1 as a nuclear factor in the photoperiodic regulation of reproduction of Physcomitrella.
authors.affiliation: Graduate School of Information Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Shimizu
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Ichikawa
authors.forename: Setsuyuki
authors.initials: S
authors.lastname: Aoki
mesh_terms: D000595:Amino Acid Sequence; D029681:Arabidopsis Proteins / Q000737:chemistry; D019068:Bryopsida / Q000235:genetics* / Q000378:metabolism; D002467:Cell Nucleus / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000737:chemistry; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D017440:Photoperiod; D017434:Protein Structure, Tertiary; D014157:Transcription Factors / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*
chemical_list: D029681:Arabidopsis Proteins; C092776:CONSTANS protein, Arabidopsis; D004268:DNA-Binding Proteins; D014157:Transcription Factors