A MAPKK kinase gene regulates extra-embryonic cell fate in Arabidopsis.
The Arabidopsis zygote divides asymmetrically into an embryonic apical cell and a basal cell with mostly extra-embryonic fate. This fundamental asymmetry sets the stage for further embryonic development, but the events mediating it are poorly understood. We have identified a MAPKK kinase gene, named YODA, that promotes extra-embryonic cell fates in the basal lineage. In loss-of-function mutants, the zygote does not elongate properly, and the cells of the basal lineage are eventually incorporated into the embryo instead of differentiating the extra-embryonic suspensor. Gain-of-function alleles cause exaggerated growth of the suspensor and can suppress embryonic development to a degree where no recognizable proembryo is formed. Our results imply that a MAP kinase cascade acts as a molecular switch promoting extra-embryonic fate.
Lukowitz
Wolfgang
W
Department of Plant Biology, 260 Panama Street, Stanford University, Stanford, CA 94305, USA.
Roeder
Adrienne
A
Parmenter
Dana
D
Somerville
Chris
C
D000595:Amino Acid Sequence / Q000235:genetics; D017360:Arabidopsis / Q000196:embryology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000302:isolation & purification*; D001483:Base Sequence / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics; D019070:Cell Lineage / Q000235:genetics*; D018076:DNA, Complementary / Q000032:analysis / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D020930:MAP Kinase Kinase Kinases / Q000235:genetics / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D012639:Seeds / Q000196:embryology* / Q000235:genetics / Q000378:metabolism
D029681:Arabidopsis Proteins; D018076:DNA, Complementary; D020930:MAP Kinase Kinase Kinases; C481302:YODA protein, Arabidopsis