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CLO/GFA1 and ATO are novel regulators of gametic cell fate in plants
Author(s) -
Moll Cordula,
Von Lyncker Ludwig,
Zimmermann Steffi,
Kägi Christina,
Baumann Nadine,
Twell David,
Grossniklaus Ueli,
GroßHardt Rita
Publication year - 2008
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2008.03650.x
Subject(s) - spliceosome , biology , egg cell , cell fate determination , gametophyte , ovule , arabidopsis , rna splicing , genetics , microbiology and biotechnology , splicing factor , mutant , alternative splicing , cell , transcription factor , rna , embryo , gene , botany , messenger rna , pollen
Summary The formation of gametes is a key step in the life cycle of any sexually reproducing organism. In flowering plants, gametes develop in haploid structures termed gametophytes that comprise a few cells. The female gametophyte forms gametic cells and flanking accessory cells. During a screen for regulators of egg‐cell fate, we isolated three mutants, lachesis ( lis ), clotho ( clo ) and atropos ( ato ), that show deregulated expression of an egg‐cell marker. We have previously shown that, in lis mutants, which are defective for the splicing factor PRP4, accessory cells can differentiate gametic cell fate. Here, we show that CLOTHO/GAMETOPHYTIC FACTOR 1 ( CLO/GFA1 ) is necessary for the restricted expression of egg‐ and central‐cell fate and hence reproductive success. Surprisingly, infertile gametophytes can be expelled from the maternal ovule tissue, thereby preventing the needless allocation of maternal resources to sterile tissue. CLO/GFA1 encodes the Arabidopsis homologue of Snu114, a protein that is considered to be an essential component of the spliceosome. In agreement with their proposed role in pre‐mRNA splicing, CLO/GFA1 and LIS co‐localize to nuclear speckles. Our data also suggest that CLO/GFA1 is necessary for the tissue‐specific expression of LIS . Furthermore, we demonstrate that ATO encodes the Arabidopsis homologue of SF3a60, a protein that has been implicated in pre‐spliceosome formation. Our results thus establish that the restriction of gametic cell fate is specifically coupled to the function of various core spliceosomal components.