Far Upstream Element-Binding Protein 1 Binds the 3' Untranslated Region of PKD2 and Suppresses Its Translation

Area of Science:

• Molecular Biology
• Genetics
• Developmental Biology

Background:

• Autosomal dominant polycystic kidney disease (ADPKD) pathogenesis involves altered polycystic kidney disease 1 (PKD1) or polycystic kidney disease 2 (PKD2) gene dosage.
• Mechanisms controlling PKD2 expression are not fully understood, hindering gene dosage compensation strategies.

Purpose of the Study:

• To investigate the regulatory mechanisms of PKD2 expression, focusing on its 3' untranslated region (3'UTR).
• To identify proteins that bind the PKD2 3'UTR and modulate its expression.

Main Methods:

• Dual-luciferase assays in cultured mammalian cells to assess 3'UTR activity.
• Pull-down assays and mass spectrometry to identify 3'UTR-binding proteins.
• In vitro protein overexpression and morpholino-based knockdown in zebrafish embryos.
• Analysis of zebrafish disease phenotypes, including tail curling and pronephric cyst formation.

Main Results:

• The PKD2 3'UTR, specifically fragment 3FI (nucleotides 691-1044), repressed luciferase and PKD2 expression.
• Far upstream element-binding protein 1 (FUBP1) was identified as a 3FI-binding protein.
• FUBP1 overexpression inhibited PKD2 protein but not mRNA levels, and FUBP1 knockdown in zebrafish increased PKD2 expression and ameliorated PKD2 KD phenotypes.
• FUBP1 overexpression in zebrafish induced ADPKD-like phenotypes, and FUBP1 interacts with eukaryotic translation initiation factor 4E-binding protein 1.

Conclusions:

• FUBP1 binds the PKD2 3'UTR (3FI) to inhibit PKD2 translation.
• FUBP1 acts as a negative regulator of PKD2 expression.
• This regulatory axis influences zebrafish disease phenotypes relevant to ADPKD, suggesting FUBP1 as a potential therapeutic target.