Gene Regulation via the Combination of Transcription Factors in the INDETERMINATE DOMAIN and GRAS Families

• Main Authors: Takuya Aoyanagi, Shun Ikeya, Atsushi Kobayashi, Akiko Kozaki
• Format: Article
• Language: English
• Published: MDPI AG 2020-06-01
• Series: Genes
• Subjects: INDETERMINATE DOMAIN (IDD) family; GRAS family; DELLA; SCARECROW (SCR); SHORT-ROOT (SHR); SCARECROW-LIKE 3 (SCL3)
• Online Access: https://www.mdpi.com/2073-4425/11/6/613

INDETERMINATE DOMAIN (IDD) family proteins are plant-specific transcription factors. Some <i>Arabidopsis</i> IDD (AtIDD) proteins regulate the expression of <i>SCARECROW</i> (<i>SCR</i>) by interacting with GRAS family transcription factors SHORT-ROOT (SHR) and SCR, which are involved in root tissue formation. Some AtIDD proteins regulate genes involved in the synthesis (<i>GA3ox1</i>) or signaling (<i>SCL3</i>) of gibberellic acid (GA) by interacting with DELLA proteins, a subfamily of the GRAS family. We analyzed the DNA binding properties and protein–protein interactions of select AtIDD proteins. We also investigated the transcriptional activity of the combination of AtIDD and GRAS proteins (AtIDD proteins combined with SHR and SCR or with REPRESSOR of <i>ga1-3</i> (RGA)) on the promoters of <i>SCR,</i> <i>SCL3</i>, and <i>GA3ox1</i> by conducting a transient assay using <i>Arabidopsis</i> culture cells. Our results showed that the <i>SCR</i> promoter could be activated by the IDD and RGA complexes and that the <i>SCL3</i> and <i>GA3ox1</i> promoters could be activated by the IDD, SHR, and SCR complexes, indicating the possibility that these complexes regulate and consequently coordinate the expression of genes involved in GA synthesis (<i>GA3ox1</i>), GA signaling (<i>SCL3</i>), and root formation (<i>SCR</i>).