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ZSCAN4 and TRF1: A functionally indirect interaction in cancer cells independent of telomerase activity
Kyungwoo Lee1, Lauren S Gollahon2
1Department of Biological Sciences, Texas Tech University, Lubbock, TX, 79409, USA.
Purpose:
Recently, the newly identified embryonic stem cell marker, Zinc finger and SCAN domain containing 4 gene (ZSCAN4), which plays a key role in genomic stability by regulating telomere elongation, was shown to co-localize with TRF1 foci. This suggests that the interaction of ZSCAN4 with TRF1 functions in regulation of telomere elongation in ESC. Based on these studies, we hypothesized that ZSCAN4 binds to TRF1 in cancer cells to function in regulating telomere length. The purpose of this study was to determine whether this interaction occurred across different cell lineage-derived cancers and whether telomerase status impacted this relationship. To that end, telomerase positive cervical cancer cells (HeLa) and breast cancer cells (MCF7), and telomerase negative osteosarcoma cells (SaOS2), were analyzed for ZSCAN4 and TRF1 interactions.
Results:
Immunocytochemistry demonstrated co-localization of ZSCAN4 and TRF1 to the nucleus. This functional relationship was confirmed using BiFC imaging analysis based on distance in situ. Co-immunoprecipitation and pull-down assay results demonstrated that ZSCAN4 binds with TRF1 in vitro indirectly. All three cell types showed similar results.
Conclusions:
In this study, we revealed, for the first time, that ZSCAN4 indirectly interacts with TRF1 (functional association protein) in cancer cells. Furthermore, we show that ZSCAN4 plays an important role independent of telomere maintenance pathways (telomerase positive and ALT) or cell lineage.
Insights
Zinc finger and SCAN domain containing 4 gene (ZSCAN4) indirectly binds to TRF1 in cancer cells. This interaction is crucial for genomic stability and occurs independently of telomere maintenance pathways or cell lineage.
Area of Science:
- Molecular Biology
- Cancer Research
- Genomics
Background:
- The Zinc finger and SCAN domain containing 4 gene (ZSCAN4) is an embryonic stem cell marker vital for genomic stability.
- ZSCAN4 regulates telomere elongation and has been observed to co-localize with TRF1 foci.
- This suggests a potential role for ZSCAN4-TRF1 interaction in telomere length regulation.
Purpose of the Study:
- To investigate if ZSCAN4 binds to TRF1 in various cancer cell types.
- To determine if telomerase status influences the ZSCAN4-TRF1 interaction.
- To analyze this interaction in telomerase-positive (HeLa, MCF7) and telomerase-negative (SaOS2) cancer cells.
Main Methods:
- Immunocytochemistry for nuclear co-localization.
- Bimolecular Fluorescence Complementation (BiFC) imaging for in situ interaction.
- Co-immunoprecipitation and pull-down assays for in vitro binding.
Main Results:
- ZSCAN4 and TRF1 co-localized within the nucleus across all tested cancer cell lines.
- BiFC analysis confirmed this functional relationship in situ.
- Co-immunoprecipitation and pull-down assays demonstrated an indirect binding of ZSCAN4 with TRF1 in vitro.
Conclusions:
- ZSCAN4 indirectly interacts with TRF1 in cancer cells, a novel finding.
- This interaction is independent of telomere maintenance pathways (telomerase-positive and ALT) and cell lineage.
- ZSCAN4 plays a significant role in cancer cell biology irrespective of these factors.
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