Gene expression

Definition

Gene expression is the process by which information encoded in a gene is translated into a functional product, typically a protein. This involves several steps including transcription, where DNA is converted to messenger RNA (mRNA), followed by translation, where mRNA is decoded to produce proteins. The regulation of gene expression ensures that genes are activated or silenced at the right times and in the right cell types, which is crucial for maintaining cellular functions and responding to environmental signals.

5 Must Know Facts For Your Next Test

1. Gene expression can be regulated at multiple levels, including transcriptional, post-transcriptional, translational, and post-translational modifications.
2. In eukaryotic cells, gene expression involves complex processes such as splicing, where introns are removed from pre-mRNA before it is translated into proteins.
3. Receptor Tyrosine Kinases (RTKs) play a crucial role in gene expression by initiating signaling pathways that lead to the activation of transcription factors.
4. The binding of transcription factors to specific DNA sequences near a gene can either enhance or inhibit its expression, thus influencing cellular responses.
5. Environmental factors such as nutrients, stress, and hormones can impact gene expression, leading to adaptive responses in cells.

Review Questions

• How do transcription factors influence gene expression and what role do they play in cellular responses?
  • Transcription factors are proteins that bind to specific DNA sequences and regulate the transcription of nearby genes. They can enhance or inhibit gene expression by promoting or blocking the assembly of the transcription machinery at the promoter region of a gene. In response to various signals, such as hormones or growth factors, these transcription factors help cells adapt their gene expression profiles to meet changing conditions and ensure proper function.
• Discuss the significance of Receptor Tyrosine Kinases (RTKs) in regulating gene expression during signal transduction pathways.
  • Receptor Tyrosine Kinases (RTKs) are key components in signal transduction pathways that relay external signals from growth factors and hormones into the cell. Upon ligand binding, RTKs undergo dimerization and autophosphorylation, activating downstream signaling cascades that ultimately lead to the activation of transcription factors. This process allows cells to alter their gene expression patterns in response to external stimuli, facilitating processes such as cell growth, differentiation, and survival.
• Evaluate how epigenetic modifications can affect gene expression and contribute to long-term changes in cellular behavior.
  • Epigenetic modifications, such as DNA methylation and histone modification, play a critical role in regulating gene expression without changing the underlying DNA sequence. These changes can affect how tightly DNA is packaged, influencing whether genes are accessible for transcription. Epigenetic modifications can be stable and heritable, meaning they can lead to long-term changes in cellular behavior and phenotype even when the initial environmental triggers are no longer present. This has significant implications for development, disease progression, and cellular memory.

Related terms

Transcription: The process of synthesizing RNA from a DNA template, where the information in a gene is copied into mRNA.

Translation: The process by which ribosomes synthesize proteins using the information contained in mRNA.

Epigenetics: The study of changes in gene expression that do not involve alterations to the underlying DNA sequence, often influenced by environmental factors.