Towards a functional classification of pathogenic FOXL2 mutations using transactivation reporter systems

Area of Science:

• Genetics
• Molecular Biology
• Endocrinology

Background:

• Mutations in the FOXL2 gene are linked to Blepharophimosis-Ptosis-Epicanthus Inversus Syndrome (BPES).
• BPES can be associated with premature ovarian failure (POF), but predicting this link from genotype is challenging due to exceptions.
• Existing knowledge lacks clear correlations between mutant FOXL2 protein behavior (aggregation, localization) and BPES type.

Purpose of the Study:

• To investigate the molecular and functional effects of FOXL2 mutants.
• To establish a functional classification framework for FOXL2 variants to predict POF risk.
• To explore correlations between subcellular mislocalization/aggregation of mutant FOXL2 and BPES type.

Main Methods:

• Analysis of 10 known FOXL2 mutants associated with BPES (with or without POF).
• Assessment of transcriptional activity of FOXL2 variants using reporter promoter assays.
• Evaluation of subcellular localization and aggregation patterns of mutant FOXL2 forms.

Main Results:

• A correlation was found between the transcriptional activity of FOXL2 variants and the type of BPES.
• Reporter assays allowed functional classification and assessment of POF risk for 18 missense mutations.
• Subcellular mislocalization and intranuclear aggregation of mutant FOXL2 were correlated with BPES type and potential ovarian dysfunction.

Conclusions:

• A functional classification tool based on transcriptional activity can help predict POF risk in BPES patients.
• Subcellular mislocalization and aggregation of mutant FOXL2 serve as potential indicators of ovarian dysfunction.
• This study provides a framework to improve the genotype-phenotype correlation for FOXL2 mutations in BPES.