Cys1 is a gene associated with autosomal recessive polycystic kidney disease (ARPKD). Mutations in Cys1, along with PKHD1 and DZIP1L, can cause this disease [1]. ARPKD is characterized by cyst development in the kidney due to defects in primary cilia function [1]. The protein encoded by Cys1, cystin, may play a role in renal tubular differentiation and the associated gene regulatory network [2].

In mice, disruption of the transcription factor Tfap2b leads to a phenotype resembling ARPKD, with cystic dilatation of the kidney distal tubules and collecting ducts [2]. Tfap2b binds to the upstream regulatory regions of both Pkhd1 and Cys1, activating their promoters, suggesting that it participates in a renal epithelial cell gene regulatory network including these two genes [2]. Disrupting this network impairs renal tubular differentiation, causing ductal dilatation, the hallmark of recessive PKD [2].

In conclusion, Cys1 is a minor gene involved in ARPKD. Studies in mouse models, especially those related to the role of Tfap2b in regulating Cys1, have enhanced our understanding of how disruptions in the gene regulatory network involving Cys1 can lead to the development of ARPKD. This contributes to the knowledge of the disease mechanism and may potentially aid in the development of targeted therapies for ARPKD.

References:

1. Yang, Hana, Sieben, Cynthia J, Schauer, Rachel S, Harris, Peter C. . Genetic Spectrum of Polycystic Kidney and Liver Diseases and the Resulting Phenotypes. In Advances in kidney disease and health, 30, 397-406. doi:10.1053/j.akdh.2023.04.004. https://pubmed.ncbi.nlm.nih.gov/38097330/

2. Wu, Maoqing, Harafuji, Naoe, O'Connor, Amber K, Caldovic, Ljubica, Guay-Woodford, Lisa M. 2023. Transcription factor Ap2b regulates the mouse autosomal recessive polycystic kidney disease genes, Pkhd1 and Cys1. In Frontiers in molecular biosciences, 9, 946344. doi:10.3389/fmolb.2022.946344. https://pubmed.ncbi.nlm.nih.gov/36710876/