Briefly describe the process of how hormones alter the DNA transcription process:
Hormones play a crucial role in regulating various physiological processes in the body, including growth, metabolism, reproduction, and homeostasis
Hormones play a crucial role in regulating various physiological processes in the body, including growth, metabolism, reproduction, and homeostasis. One of the ways hormones exert their effects is by altering the DNA transcription process, which involves the synthesis of messenger RNA (mRNA) from a DNA template. Here is a detailed explanation of how hormones bring about changes in DNA transcription:
1. Reception: Hormones are released by endocrine glands and travel through the bloodstream to reach their target cells. Each hormone typically binds to specific hormone receptors on the surface or inside the target cells.
2. Activation of hormone-receptor complex: When a hormone binds to its receptor, it triggers a conformational change in the receptor, leading to the activation of the hormone-receptor complex. This complex serves as a transcription factor, a protein that exerts influence on the transcription process.
3. Translocation to the nucleus: Hormone-receptor complexes that are activated at the cell membrane move into the cell nucleus. If the receptor is already inside the nucleus, no translocation is required.
4. Binding to DNA: Once inside the nucleus, the hormone-receptor complex binds to specific DNA sequences in the promoter region of target genes. These DNA sequences are called hormone response elements (HREs) or hormone-specific response elements (HSREs).
5. Recruitment of coactivators and corepressors: The hormone-receptor complex recruits specific coactivator proteins or corepressor proteins to the DNA. Coactivators enhance transcription, while corepressors repress it. These proteins help modulate the gene expression induced by the hormone.
6. Alteration of chromatin structure: Coactivator and corepressor proteins, in collaboration with the hormone-receptor complex, can modify the structure of the chromatin, the complex of DNA and proteins. This modification can lead to chromatin remodeling, making the DNA more accessible or condensed, respectively.
7. Interaction with transcription machinery: The hormone-receptor complex interacts with the transcription machinery at the promoter region of the target gene. It can recruit or release various transcription factors and enzymes involved in RNA synthesis, such as RNA polymerase II.
8. Initiation of transcription: The complex of transcription factors, enzymes, and the hormone-receptor complex initiates the synthesis of mRNA by RNA polymerase II. RNA polymerase transcribes the DNA template into mRNA, which carries the genetic information for protein synthesis.
9. Post-transcriptional modifications: After transcription, the newly synthesized mRNA undergoes several modifications, such as capping, splicing, and polyadenylation, to form a mature mRNA molecule ready for translation.
The alterations in the DNA transcription process caused by hormones ultimately result in the production of specific proteins that mediate the physiological effects of the hormone. This intricate regulatory mechanism ensures the precise control of gene expression in response to hormonal signals.
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