TOP1 Bovine

DNA Topoisomerase-I (Top1) is responsible for relieving torsional stress in DNA that arises during processes such as transcription, replication, and chromatin assembly . It achieves this by creating a transient single-stranded break in the DNA, allowing the DNA strands to pass through one another and thereby reducing supercoiling . This action is essential for the proper functioning of the cell, as excessive supercoiling can hinder the progress of replication and transcription machinery.

Top1 belongs to the type I topoisomerases, which are characterized by their ability to cut one strand of the DNA duplex . The enzyme forms a covalent bond with the DNA at the site of the break, creating a temporary DNA-protein complex. This complex allows the DNA to swivel around the intact strand, relieving the torsional stress. Once the stress is relieved, the enzyme reseals the break, restoring the integrity of the DNA molecule .

DNA topoisomerases are evolutionarily conserved enzymes, indicating their fundamental role in cellular biology . They are divided into several families based on their sequence and structural characteristics. Top1, specifically, belongs to the IB family, which is distinct in its reaction mechanism and structural fold .

In bovines, as in other mammals, Top1 is essential for normal cellular function. It is involved in various physiological processes, including gene expression regulation and DNA repair . The enzyme’s activity is regulated by phosphorylation, which can modulate its ability to relax supercoiled DNA and its sensitivity to inhibitors such as camptothecin .

Top1 inhibitors are widely used in cancer therapy due to their ability to trap the enzyme-DNA complex, leading to DNA damage and cell death . Understanding the function and regulation of bovine Top1 can provide insights into the development of new therapeutic strategies and enhance our knowledge of DNA dynamics in mammalian cells.