title: Two splice variants of the IDD14 transcription factor competitively form nonfunctional heterodimers which may regulate starch metabolism.
abstract: Alternative splicing of primary gene transcripts provides eukaryotic cells, with a critical scheme for enriching transcriptome and proteome diversity. Here we report that alternative splicing of the Arabidopsis INDERMINATE DOMAIN 14 (IDD14) transcription factor gene generates a competitive inhibitor in regulating starch metabolism. An alternatively spliced IDD14 form (IDD14β), which is produced predominantly under cold conditions, lacks functional DNA-binding domain but is able to form heterodimers with the functional IDD14 form (IDD14α). IDD14α-IDD14β heterodimers have reduced binding activity to the promoter of Qua-Quine Starch (QQS) gene that regulates starch accumulation. Transgenic Arabidopsis plants overproducing IDD14α (35S:IDD14α) exhibited retarded growth with pale green leaves as appeared on QQS-overexpressing plants. Notably, IDD14β overproduction rescued the 35S:IDD14α phenotypes. We propose that alternative splicing of the IDD14 gene generates a self-controlled regulatory loop that may modulate starch accumulation in response to cold.
authors.affiliation: Department of Chemistry, Seoul National University, Seoul 151-742, Korea.
authors.forename: Pil Joon
authors.initials: PJ
authors.lastname: Seo
authors.forename: Mi Jung
authors.initials: MJ
authors.lastname: Kim
authors.forename: Jae-Yong
authors.initials: JY
authors.lastname: Ryu
authors.forename: Eun-Young
authors.initials: EY
authors.lastname: Jeong
authors.forename: Chung-Mo
authors.initials: CM
authors.lastname: Park
mesh_terms: D017398:Alternative Splicing / Q000235:genetics*; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003080:Cold Temperature; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D014644:Genetic Variation; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D055503:Protein Multimerization; D020543:Proteome / Q000235:genetics / Q000378:metabolism; D013213:Starch / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; D020543:Proteome; D014157:Transcription Factors; C562191:indeterminate(ID)-domain 14 protein, Arabidopsis; D013213:Starch