fyi :: incl. ancestral expression reconstruction
Intronic regulatory elements determine the divergent expression
patterns of AGAMOUS-LIKE6 subfamily members in Arabidopsis
Stephen E. Schauer 1 , Philipp M. Schlüter 1 , Ramarmurthy Baskar 1,2,†
, Jacqueline Gheyselinck 1,‡ , Arturo Bolaños 1 , Mark D. Curtis 1 and
Ueli Grossniklaus 1,2,*
The screening of enhancer detector lines in Arabidopsis thaliana has
identified genes that are specifically expressed in the sporophytic
tissue of the ovule. One such gene is the MADS-domain transcription
factor AGAMOUS-LIKE6 (AGL6), which is expressed asymmetrically in the
endothelial layer of the ovule, adjacent to the developing haploid
female gametophyte. Transcription of AGL6 is regulated at multiple
stages of development by enhancer and silencer elements located in both
the upstream regulatory region and the large first intron. These
include a bipartite enhancer, which requires elements in both the
upstream regulatory region and the first intron, active in the
endothelium. Transcription of the AGL13 locus, which encodes the other
member of the AGL6 subfamily in Arabidopsis, is also regulated by
elements located in the upstream regulatory region and in the first
intron. There is, however, no overlapping expression of AGL6 and AGL13
except in the chalaza of the developing ovule, as was shown using a
dual gene reporter system. Phylogenetic shadowing of the first intron
of AGL6 and AGL13 homologs from other Brassicaceae identified four
regions of conservation that probably contain the binding sites of
transcriptional regulators, three of which are conserved outside
Brassicaceae. Further phylogenetic analysis using the protein-encoding
domains of AGL6 and AGL13 revealed that the MADS DNA-binding domain
shows considerable divergence. Together, these results suggest that
AGL6 and AGL13 show signs of subfunctionalization, with divergent
expression patterns, regulatory sequences and possibly functions.
http://www3.interscience.wiley.com/journal/122389205/abstract
--
Klaas Vandepoele, PhD
Tel. 32 (0)9 33 13822
VIB Department of Plant Systems Biology, Ghent University
Technologiepark 927, 9052 Gent, Belgium
E-mail: Klaas.Vandepoele@psb.vib-ugent.be
Website: http://bioinformatics.psb.ugent.be/
---------------------------------------------------------
Come on out and change the world (around us)