Reference "GIGANTEA: a circadian clock-controlled gene that regulates photoperiodic flowering in Arabidopsis and encodes a protein with several possible membrane-spanning domains"

Reference ID

6519

Title

GIGANTEA: a circadian clock-controlled gene that regulates photoperiodic flowering in Arabidopsis and encodes a protein with several possible membrane-spanning domains

Source

The EMBO journal, 1999, vol. 18, pp. 4679-4688

Authors (8)

Fowler-S	Lee-K
Onouchi-H	Samach-A
Richardson-K	Morris-B
Coupland-G	Putterill-J

Abstract

Flowering of Arabidopsis is promoted by long days and delayed by short days.
Mutations in the GIGANTEA (GI) gene delay flowering under long days but have
little or no effect under short days. We have now isolated the GI gene and show
that it encodes a novel, putative membrane protein. By comparing the sequence of
the Arabidopsis gene with that of a likely rice orthologue and by sequencing
mutant alleles, we identify regions of the GI protein that are likely to be
important for its function. We show that GI expression is regulated by the
circadian clock with a peak in transcript levels 8-10 h after dawn. The timing,
height and duration of this peak are influenced by daylength. We analysed the
interactions between GI and the LHY, CCA1 and ELF3 genes, previously shown to
affect daylength responses; we show that the rhythmic pattern of GI expression
is altered in the elf3, CCA1-OX and lhy genotypes, and that CCA1 and LHY
expression are reduced by gi mutations. Our results are consistent with the idea
that GI plays an important role in regulating the expression of flowering time
genes during the promotion of flowering by photoperiod.