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Updated: Mar 24, 2026
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Published on: August 29, 2025
Structural and biological function of NYD-SP15 as a new member of cytidine deaminases
Yidan Xu1, Lei Li2, Jianmin Li1
1Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China.
Abstract:
Recent studies were mainly focus on the cytidine deaminase family genes, which contained a lot of members that varied on the function of catalytic deamination in RNA or DNA and were involved in the process of growth maintenance, host immunity, retroviral infection, tumorigenesis, and drug resistance with a feature of C-U deamination. In this study, we identified a new member of cytidine deaminase family, NYD-SP15. Previous work showed that the deduced structure of the protein contained two dCMP_cyt_deam domains, which were involved in zinc ion binding. NYD-SP15 was expressed variably in a wide range of tissues, indicating its worthy biological function and creative significances. Sequence analysis, RT-PCR, western blot, flow cytometry, direct-site mutation and GST pull-down assay were performed to analyze the construction and function of NYD-SP15. The results in our studies showed that NYD-SP15 was closely related to deoxycytidylate deaminase and cytidine deaminase, with authentic cytidine deaminase activity in vivo and vitro as well as homo dimerization effects. NYD-SP15 contained nuclear localization sequence (NLS) and nuclear export-signal (NES) and could dynamically shuttle between the nucleus and cytoplasm. Furthermore, NYD-SP15 gene over-expression reduced the cells growth and blocked G1 to S phase, which implied a potential inhibition effect on cell growth.
Insights
We identified NYD-SP15, a novel cytidine deaminase family member with catalytic activity. Overexpression of NYD-SP15 inhibits cell growth by blocking the G1 to S phase transition.
Area of Science:
- Biochemistry
- Molecular Biology
- Genetics
Background:
- Cytidine deaminase family members play crucial roles in RNA/DNA deamination.
- These enzymes are implicated in diverse biological processes including immunity, tumorigenesis, and drug resistance.
- NYD-SP15 is a newly identified member of this important gene family.
Purpose of the Study:
- To identify and characterize a novel cytidine deaminase family member, NYD-SP15.
- To investigate the enzymatic activity, cellular localization, and functional impact of NYD-SP15.
- To explore the potential role of NYD-SP15 in cell growth regulation.
Main Methods:
- Sequence analysis and RT-PCR for gene characterization.
- Western blot and flow cytometry for protein expression and cell cycle analysis.
- Site-directed mutagenesis and GST pull-down assays to study protein interactions and localization.
Main Results:
- NYD-SP15 exhibits homology to deoxycytidylate and cytidine deaminases with in vitro and in vivo catalytic activity.
- NYD-SP15 possesses both nuclear localization sequence (NLS) and nuclear export-signal (NES), enabling nucleocytoplasmic shuttling.
- NYD-SP15 overexpression leads to reduced cell growth and G1 to S phase arrest.
Conclusions:
- NYD-SP15 is a functional cytidine deaminase with dynamic subcellular localization.
- NYD-SP15 plays a significant role in regulating cell cycle progression.
- NYD-SP15 represents a potential therapeutic target for inhibiting cell proliferation in diseases like cancer.
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