Regulation of Translation In Eukaryotes


One of the ways that translation can be regulated in eukaryotes is by altering the genes that encode the proteins. Genes can undergo various changes that affect their expression and function, such as:

  • Gene loss or deletion: Some genes can be lost or partially lost from cells, either by mutations or by chromosomal rearrangements. This can result in the absence of functional proteins that are normally produced from those genes. For example, during the differentiation of red blood cells, some genes are deleted from the genome, such as those encoding ribosomal RNA and histones.
  • Gene amplification: Some genes can be duplicated or multiplied in the genome, leading to an increased number of copies of those genes. This can result in higher levels of protein production from those genes. For example, some cancer cells become resistant to the drug methotrexate by amplifying the gene for the enzyme dihydrofolate reductase, which is inhibited by the drug.
  • Gene rearrangement: Some genes can be moved or rearranged in the genome, either by translocation, inversion, or transposition. This can result in different combinations of gene segments or different associations of genes with regulatory elements. For example, in B cells that produce antibodies, various segments of DNA encoding different parts of the antibody molecule are rearranged to generate diverse antibodies.
  • Gene modification: Some genes can be modified at the level of DNA, such as by methylation or demethylation of cytosine bases. This can affect the accessibility and activity of those genes by influencing their interaction with transcription factors and chromatin modifiers. For example, cytosine methylation often occurs in CpG islands within promoter regions of genes, and the greater the extent of methylation, the less readily a gene is transcribed .

These changes in genes can have profound effects on the translation of proteins and the phenotypes of cells and organisms. They can also provide a source of genetic variation and evolution.