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Updated: May 13, 2026
Assessment of Zebrafish Lens Nucleus Localization and Sutural Integrity
Published on: May 6, 2019
HSF4 regulates DLAD expression and promotes lens de-nucleation
Xiukun Cui1, Lei Wang, Jing Zhang
1Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Huazhong University of Science and Technology, Wuhan, Hubei 430074, PR China.
Abstract:
HSF4 mutations lead to both congenital and age-related cataract. The purpose of this study was to explore the mechanism of cataract formation caused by HSF4 mutations. The degradation of nuclear DNA is essential for the lens fiber differentiation. DNase 2β (DLAD) is highly expressed in lens cells, and mice with deficiencies in the DLAD gene develop nuclear cataracts. In this study, we found that HSF4 promoted the expression and DNase activity of DLAD by directly binding to the DLAD promoter. In contrast, HSF4 cataract causative mutations failed to bind to the DLAD promoter, abrogating the expression and DNase activity of DLAD. These results were confirmed by HSF4 knockdown in zebrafish, which led to incomplete de-nucleation of the lens and decreased expression and activity of DLAD. Together, our results suggest that HSF4 exerts its function on lens differentiation via positive regulation of DLAD expression and activity, thus facilitating de-nucleation of lens fiber cells. Our demonstration that HSF4 cataract causative mutations abrogate the induction of DLAD expression reveals a novel molecular mechanism regarding how HSF4 mutations cause cataractogenesis.
Insights
Heat shock transcription factor 4 (HSF4) mutations cause cataracts by disrupting lens cell development. HSF4 normally promotes DNase 2 beta (DLAD) expression, essential for nuclear DNA degradation during lens fiber differentiation.
Area of Science:
- Ophthalmology
- Molecular Biology
- Genetics
Background:
- Heat shock transcription factor 4 (HSF4) mutations are linked to congenital and age-related cataracts.
- Lens fiber differentiation requires nuclear DNA degradation.
- DNase 2 beta (DLAD) is crucial for lens development, and its deficiency causes cataracts in mice.
Purpose of the Study:
- To investigate the molecular mechanism by which HSF4 mutations lead to cataract formation.
- To elucidate the role of HSF4 in regulating DLAD expression and activity in lens cells.
Main Methods:
- Investigated HSF4's interaction with the DLAD promoter using molecular biology techniques.
- Analyzed the impact of HSF4 mutations on DLAD expression and DNase activity.
- Utilized HSF4 knockdown in zebrafish to confirm findings in a whole organism model.
Main Results:
- HSF4 directly binds to the DLAD promoter, promoting its expression and DNase activity.
- Cataract-associated HSF4 mutations failed to bind the DLAD promoter, leading to reduced DLAD expression and activity.
- HSF4 knockdown in zebrafish resulted in incomplete lens de-nucleation and decreased DLAD function.
Conclusions:
- HSF4 regulates lens fiber cell de-nucleation by positively controlling DLAD expression and activity.
- HSF4 mutations disrupt cataractogenesis by abrogating DLAD induction, revealing a novel molecular mechanism for inherited cataracts.
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