TFL2/LHP1 is involved in auxin biosynthesis through positive regulation of YUCCA genes.
TERMINAL FLOWER2 (TFL2) is the plant homologue of metazoan HETEROCHROMATIN PROTEIN1 (HP1) protein family. It is known that, unlike most HP1 proteins, TFL2 does not primarily localize to heterochromatin; instead it functions in regulation of specific genes in euchromatic regions. We show that the tfl2 mutant has a lower rate of auxin biosynthesis, resulting in low levels of auxin. In line with this, tfl2 mutants have lower levels of expression of auxin response genes and retain an auxin response. The reduced rate of auxin biosynthesis in tfl2 is correlated to the down-regulation of specific genes in the tryptophan-dependent auxin biosynthesis pathway, a sub-set of the YUCCA genes. In vivo, TFL2 is targeted to a number of the YUCCA genes in an auxin-dependent fashion revealing a role of TFL2 in auxin regulation, probably as a component of protein complexes affecting transcriptional control.
Evolutionary Biology Center, Physiological Botany, Uppsala University, SE-752 36 Uppsala, Sweden.
Kristina
K
Rizzardi
Katarina
K
Landberg
Lars
L
Nilsson
Karin
K
Ljung
Annika
A
Sundås-Larsson
D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics* / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D015536:Down-Regulation; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D007210:Indoleacetic Acids / Q000378:metabolism*; D005810:Multigene Family; D009154:Mutation; D010105:Oxygenases / Q000235:genetics* / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000096:biosynthesis*; D030821:Plants, Genetically Modified
D029681:Arabidopsis Proteins; D002868:Chromosomal Proteins, Non-Histone; D017931:DNA Primers; D007210:Indoleacetic Acids; D010105:Oxygenases; D010937:Plant Growth Regulators; C477788:At5g17690 protein, Arabidopsis; C422746:YUC protein, Arabidopsis