The Gene Encodes a NOT1 Subunit of the CCR4-NOT Complex and Regulates Cell Patterning in Endosperm.

Maize () () mutants form multiple aleurone layers in the endosperm and have arrested embryogenesis. Prior studies suggest that functions downstream of () in a regulatory pathway that controls aleurone cell fate and other endosperm traits. The original mutant contained an ∼2-Mb multigene deletion, which precluded identification of the causal gene. Here, ethyl methanesulfonate mutagenesis produced additional alleles, and RNA sequencing from developing endosperm was used to identify a candidate gene based on differential expression compared with the wild-type progenitor. Gene editing confirmed the gene identity by producing mutant alleles that failed to complement existing mutants and that produced multiple-aleurone homozygous phenotypes. encodes a homolog of NEGATIVE ON TATA-LESS1, a protein that acts as a scaffold for the CARBON CATABOLITE REPRESSION4-NEGATIVE ON TATA-LESS complex. This complex is highly conserved and essential in all eukaryotes for regulating a wide array of gene expression and cellular activities. Maize also harbors a duplicate locus, , which likely accounts for the ability of mutants to form viable cells. Transcriptomic analysis indicated that THK1 regulates activities involving cell division, signaling, differentiation, and metabolism. Identification of provides an important new component of the DEK1 regulatory system that patterns cell fate in endosperm.