gene expression

Definition

Target type: biologicalprocess

The process in which a gene's sequence is converted into a mature gene product (protein or RNA). This includes the production of an RNA transcript and its processing, as well as translation and maturation for protein-coding genes. [GOC:txnOH-2018, PMID:25934543, PMID:31580950]

Gene expression is the process by which the information encoded in a gene is used to synthesize a functional gene product, typically a protein. It encompasses a series of intricate steps that begin with the copying of the gene's DNA sequence into messenger RNA (mRNA) during transcription. This mRNA then serves as a blueprint for protein synthesis during translation, where ribosomes read the mRNA sequence and link amino acids in the correct order to create the protein. The process of gene expression is tightly regulated, ensuring that the appropriate proteins are produced at the right time and in the right amounts. It is a fundamental process in all living organisms and underlies a wide range of cellular functions, from metabolism and growth to development and immunity. This intricate process begins within the nucleus, where the DNA molecule, the repository of genetic information, resides. The DNA double helix unwinds, exposing the specific gene of interest. This exposed gene then serves as a template for the synthesis of mRNA, a molecule that carries the genetic code to the ribosomes, the protein-making machinery of the cell. This step, known as transcription, is mediated by an enzyme called RNA polymerase, which reads the DNA sequence and creates a complementary copy in the form of mRNA. Once transcribed, the mRNA molecule undergoes processing and is transported from the nucleus to the cytoplasm, where it encounters ribosomes. These ribosomes, in conjunction with transfer RNA (tRNA) molecules, decipher the mRNA sequence, translating each three-nucleotide codon into a specific amino acid. These amino acids are then linked together in a chain, following the order specified by the mRNA sequence, ultimately forming a functional protein. This process, called translation, culminates in the synthesis of a protein molecule, which is then folded into a three-dimensional structure, crucial for its specific function within the cell. The protein, once synthesized, can be modified further through various post-translational modifications, such as phosphorylation or glycosylation, which fine-tune its activity and stability. The regulation of gene expression is a vital aspect of cellular function, ensuring that the correct proteins are produced at the appropriate times and in the required quantities. This regulation occurs at multiple levels, including: 1) Transcriptional control: Regulating the rate at which a gene is transcribed into mRNA. This can be influenced by various factors, including the presence of specific transcription factors, which bind to DNA and either enhance or inhibit the transcription process. 2) Post-transcriptional control: Regulating the processing, stability, and transport of mRNA molecules. This step involves modifications such as splicing, where non-coding regions of the mRNA are removed, and polyadenylation, where a tail of adenine nucleotides is added, which influences mRNA stability and translation. 3) Translational control: Regulating the efficiency with which ribosomes translate mRNA into protein. This can involve factors that affect ribosome binding to mRNA or the rate of protein synthesis. 4) Post-translational control: Regulating the activity and stability of the synthesized protein through modifications such as phosphorylation, glycosylation, or proteolysis. These modifications can alter the protein's function, localization, or lifespan. In essence, gene expression is a dynamic process that allows cells to respond to their environment, adapt to changing conditions, and carry out their specialized functions. It is a fundamental principle of biology, underpinning the development, function, and health of all living organisms.'
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Proteins (32)

Compounds (772)