The effect of human GATA4 gene mutations on the activity of target gonadal promoters

Abstract

GATA transcription factors are crucial regulators of cell-specific gene expression in many tissues including the gonads. Although clinical cases of reproductive dysfunction have yet to be formally linked to GATA gene mutations, they have begun to be reported in other systems. Heterozygous GATA4 mutations have been associated with cases of congenital heart defects. Little is known, however, about the effect of these mutations on gonadal gene transcription. Since individuals carrying these mutations do not appear to suffer from gross reproductive defects, we hypothesized that this might be due to the differential transcriptional properties of the mutant proteins on heart versus gonadal target genes. Five mutations (S52F, E215D, G295S, V266M, and E359X) were recreated in the rat GATA4 protein.Several parameters were used to analyze the transcriptional properties of the mutants: activation of known gonadal target promoters (Star, Cyp19a1, and Inha), DNA binding, and interaction with GATA4 transcriptional partners. Three mutations (S52F, G295S, and E359X) reduced GATA4 transcriptional activity on the different gonadal promoters. With the exception of the G295S mutant, which showed a significant loss of DNA-binding affinity, the decrease in activity of the other GATA4 mutants was not associated with a change in DNA binding. All GATA4 mutants retained their ability to interact and cooperate with their major gonadal partners (NR5A1 and NR5A2) thereby compensating in part for the loss in intrinsic GATA4 transcriptional activity. Thus, unlike the heart, where the GATA4 mutations have deleterious effects, our data suggest that they would have a lesser impact on gonadal gene transcription and function.

Loss-of-function mutation in GATA4 causes anomalies of human testicular development

“…In contrast to the mutation described here, these mutant proteins retained at least some DNA-binding activity and showed various degrees of transcriptional activation of the gonadal promoters. These mutant proteins also retained their ability to synergize with NR5A1 (25). This may explain the apparent absence of gonadal anomalies reported in the individuals carrying these mutations (25).…”

“…The Gata4 p.V217G protein cannot interact with FOG2, and Gata4 ki/ki XY embryos show severe impairment of testis development (15,16). A number of previously described GATA4 mutations specifically associated with congenital heart defects were studied for their ability to transactivate gonadal promoters (25). In contrast to the mutation described here, these mutant proteins retained at least some DNA-binding activity and showed various degrees of transcriptional activation of the gonadal promoters.…”

“…No mutations in GATA4 have been reported in association with human cases of DSD. The absence of an associated gonadal anomaly in the reported cases of CHD associated with GATA4 mutations may also be due to the ability of the mutated GATA4 proteins to retain the ability to interact with either FOG2 or NR5A1 or both (15)(16)(17)(18)25).…”

GATA transcription factors regulate LHβ gene expression

“…In prior investigations, GATA factors were found to functionally interact with these nuclear receptors on additional genes with importance for reproductive function, including the aromatase (CYP19), inhibin a-subunit, and MIS genes (Watanabe et al 2000, Tremblay et al 2001, Tremblay & Viger 2001, Robert et al 2006. Through a series of elegant experiments, the Viger group has characterized the amino acid residues in the GATA4 protein that are required for heterodimer formation with SF-1 and LRH-1, as well as those residues required for DNA binding and transactivation (Tremblay et al 2001, Bouchard et al 2009). Similar detailed analyses regarding GATA2 protein-protein interactions have not been performed.…”

“…Despite their name, FOG proteins have been found to either augment or blunt GATA effects dependent on promoter and cell context (Cantor & Orkin 2005). Of note, GATA members have been shown to interact with multiple transcription factors with known importance for gonadotropin and GnRH receptor gene expression, including SF-1, LRH-1, Sp1, and AP1 (Kawana et al 1995, Fluck & Miller 2004, Bouchard et al 2009). …”