If the nucleus of a cell becomes damaged by a xenobiotic substance, it can prevent the cell from dividing and lead to other problems. In many cases, the damage eventually causes the death of the cell.
In addition to the nucleus itself being potentially damaged, the genetic makeup located within the nucleus could also suffer damage on its own. In this case, it often causes the cell to lose normal control of the function that regulates cell division, causing the cell to continue to divide and become a neoplasm.
The nucleus itself contains numerous different parts, such as nucleotides, enzymes, nucleoproteins and the cell nucleolus, which is a dense area within the nucleus where the DNA and RNA are stored. As the nucleus controls cell metabolism, division and protein synthesis and processes genetic information, any damage to the nucleus could easily affect any of these functions. If the DNA in the nucleus is damaged by UV rays, it typically leads to suppression of RNA synthesis and also causes the cell to initiate nucleotide excision repair.
In addition to damage to the nucleus, damage to the cell's other structures, such as the cell membrane or mitochondria, can cause numerous problems and potentially lead to the death of the cell.