Gene Expression

Gene expression is the process by which information from a gene is used to synthesize a functional gene product, typically proteins or RNA molecules. It involves several key steps:

  • Transcription: In the nucleus, DNA unwinds, and RNA polymerase binds to the promoter region of a gene to synthesize messenger RNA (mRNA). This mRNA carries genetic information from the DNA to the cytoplasm.
  • RNA processing (in eukaryotes): Pre-mRNA undergoes modifications including capping (adding a 5' cap), splicing (removing introns), and polyadenylation (adding a poly-A tail).
  • Translation: In the cytoplasm, ribosomes read the mRNA sequence and translate it into a polypeptide chain. Transfer RNA (tRNA) molecules bring amino acids to the ribosome.

Gene expression is tightly regulated by environmental signals, developmental cues, and cellular pathways. Dysregulation can lead to diseases such as cancer and genetic disorders.