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Updated: Jun 8, 2026
Detection of Alternative Splicing During Epithelial-Mesenchymal Transition
Published on: October 9, 2014
Differential detection of alternatively spliced variants of Ciz1 in normal and cancer cells using a custom
Faisal A Rahman1, Naveed Aziz, Dawn Coverley
1Department of Biology, University of York, UK.
Background:
Ciz1 promotes initiation of mammalian DNA replication and is present within nuclear matrix associated DNA replication factories. Depletion of Ciz1 from normal and cancer cells restrains entry to S phase and inhibits cell proliferation. Several alternative splicing events with putative functional consequences have been identified and reported, but many more variants are predicted to exist based on publicly available mRNAs and expressed sequence tags.
Methods:
Here we report the development and validation of a custom exon and exon-junction microarray focused on the human CIZ1 gene, capable of reproducible detection of differential splice-variant expression.
Results:
Using a pair of paediatric cancer cell lines and a pool of eight normal lines as reference, the array identified expected and novel CIZ1 splicing events. One novel variant (delta 8-12) that encodes a predicted protein lacking key functional sites, was validated by quantitative RT-PCR and found to be over-represented in a range of other cancer cell lines, and over half of a panel of primary lung tumours.
Conclusions:
Expression of CIZ1 delta 8-12 appears to be restricted to cancer cells, and may therefore be a useful novel biomarker.
Insights
A novel CIZ1 splice variant, delta 8-12, is overexpressed in various cancers. This CIZ1 variant, lacking key functional sites, shows potential as a specific cancer biomarker.
Area of Science:
- Molecular Biology
- Cancer Research
- Genetics
Background:
- The Ciz1 protein is crucial for initiating mammalian DNA replication and is found in DNA replication factories.
- Ciz1 depletion inhibits cell proliferation by restricting entry into S phase.
- While some CIZ1 splice variants are known, many more are predicted.
Purpose of the Study:
- To develop and validate a custom microarray for detecting differential expression of CIZ1 splice variants.
- To identify novel CIZ1 splice variants and analyze their expression patterns in normal and cancer cells.
Main Methods:
- Development and validation of a custom exon and exon-junction microarray for the human CIZ1 gene.
- Analysis of CIZ1 splice variant expression in paediatric cancer cell lines versus normal cell lines.
- Validation of a novel variant (delta 8-12) using quantitative RT-PCR.
Main Results:
- The microarray successfully detected known and novel CIZ1 splicing events.
- A novel variant, CIZ1 delta 8-12, predicted to lack key functional sites, was identified.
- CIZ1 delta 8-12 was over-represented in various cancer cell lines and over half of primary lung tumors analyzed.
Conclusions:
- The CIZ1 delta 8-12 splice variant is predominantly expressed in cancer cells.
- CIZ1 delta 8-12 represents a potential novel biomarker for cancer detection.
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