Regulation of gene expression in Eukaryotic cells Due to the complexity involved in eukaryotic cells, the processes of regulating gene expression may as well be complicated. As a result the process involves many different levels to effectively control the hundreds of cells in a eukaryotic organism. Regulation of gene expression in eukaryotes takes place not only during the process of transcription but also during protein synthesis since the protein produced as the final product performs the function that the expressed gene specifies. Expression of genes may be regulated during transcription (transcriptional regulation) or after transcription has already occurred (post-transcriptional regulation). Transcriptional regulation involves factors that prevent the coding of a DNA sequence into a messenger RNA or basically the mechanisms control the amount of RNA produced. The major mechanism used to regulate the transcription process is the control of the binding between the RNA polymerase and the DNA since this bond forms the bridge through which he codes would be sent. Binding of non coding molecules known as repressors to the protein that triggers the binding also controls transcription by altering the structure of the protein to either enhance or prevent the binding process. Certain molecules such as activators and enhancers may also be used in favor of transcription by promoting the bonding of polymerase and DNA to be transcribed. Post transcriptional regulation involves regulating the amount of the mRNA to be translated. This is done by splicing or capping of the some of the mRNA molecules. Gene regulation in eukaryotes may as well be translational or post translational. Translational regulatory mechanisms work by regulating the amount of mRNA to be processed into proteins. This is done by regulating the transport of these molecules from the nucleus to the cytoplasm from which translation takes place. Factors such as temperature changes have also been confirmed to alter the structures of the binding molecules resulting to antisense binding of the mRNA molecule to chromosomes. After translation has occurred, post translational mechanisms may occur in the cell such as degradation of the protein molecule formed or the proteins may be modified through addition of glucose, acetyl or fatty acid molecules (King, M.W. 2011, p. 1). Gene expression alterations and cancer Alterations in gene expression occur through many mechanisms which basically involves changing of the base sequences in the genetic material. One of the major mechanism through which gene expression is altered is addition where a base pair is added to the normal sequence hence changing the specificity of the protein that the code specifies. Addition results to production of a nonsense sequence which does not specify any of the proteins. Deletion of a base pair(s) is another common mechanism where one or more base pairs are deleted from the normal three base sequences. Similar to addition, deletion results to production of nonsense codes (base sequences which do not specify production of any protein). Another mechanism is substitution which involves replacing a specific base pair with a different one. As a result, the sequence specific for a given protein is changed to another code which in rare cases specifies t