Differentially expressed and alternately spliced genes as a novel t00l for genotoxicity: A computerized study in ATT-myc transgenic mice for the recognition of genotoxic and nongenotoxic chemical

Mansour Abdullah Alghamdi ^1,2 Eman Mohamad El nashar ^1,2* Mahmoud Elalfy ³ Norah Saeed Al-Zahrani ^1,2 Mohammed Abdullah Alshehri ² Mohammad El-Nablaway ^4,5 Khulood Mohammed Al-Khater ⁶ Rashid A Aldahhan ⁶ Eman G. El-Hadidy ^7,8 Fathy Sleem ³ Ahmed Aljazzar ⁹ Jürgen borlak ¹⁰ Mona Elhadidy ¹¹

• ¹ Department of Anatomy, College of Medicine, King Khalid University, Abha, Saudi Arabia
• ² King Khalid University, Abha, Saudi Arabia
• ³ Mansoura University, Mansoura, Dakahlia, Egypt
• ⁴ Department of Basic Medical Sciences, Faculty of Medicine, Almaarefa University, Riyadh, Saudi Arabia
• ⁵ University of Almaarefa, Riyadh, Saudi Arabia
• ⁶ Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
• ⁷ Damietta University, Damietta, Egypt
• ⁸ Faculty of Education, Damietta University, New Damietta, Damietta, Egypt
• ⁹ King Faisal University, Al-Ahsa, Eastern Province, Saudi Arabia
• ¹⁰ Institute of Biochemistry, University of Veterinary Medicine Hannover, Hannover, Lower Saxony, Germany
• ¹¹ Faculty of Medicine, Al Baha University, Al Bahah, Al Bahah, Saudi Arabia

The application of transgenic mice and gene expression studies was proven advantageous in the examination of hazardous chemicals. Mice received a weekly dose of NDEA at 75 mg/kg in saline for six weeks before they were sacrificed. Additionally, they were treated with BHT at 300 mg/kg twice per week for eight weeks. This was carried out to identify genes that showed altered expression or alternative splicing in the livers of both male and female sixth-generation transgenic animals. Using the MouseExon10ST array, we analyzed six hybridizations through a mixed-model analysis of variance. We found that 645 genes exhibited significant variations in gene expression between groups, while 181 genes displayed both gene expression differences and potential splicing variations (p < 0.01). Additionally, 2021 genes showed significant exon-group interactions, suggesting alternative splicing. A contingency table analysis that compared the examined gene set with a dataset of known pathways and gene classifications revealed that groups within the GOMolFn, GOProcess, GOCellLoc, and Pathway classes had a significantly higher representation of alternatively spliced and expressed genes (p < 0.01). One of the top ten expressed genes was TAT, which encodes the mitochondrial enzyme tyrosine aminotransferase. This enzyme is predominantly found in the liver and metabolizes tyrosine through a five-step process to produce toxic compounds. TAT is also recognized as a novel tumor suppressor gene (TSG), and its inactivation through gene deletion and hypermethylation contributes to the pathophysiology of hepatocellular carcinoma (HCC). Additionally, HNF-4, a transcription factor whose expression is downregulated in the fetal liver of albino mice, is essential for TAT expression. An expression array analysis can be used to identify genotoxic compounds when tested in the att-myc model for short-term toxicity.