An overview of gene regulation mechanisms in eukaryotes

o Transcriptional regulation . Nucleus a. Regulatory proteins and transcription factors bind to DNA W consensus DNA sequences (promoter regions) to facilitate l transcription. Pre— b. Additional regulatory DNA mRNA\/\/\/\/\ sequences (enhancers and silencers) bind regulatory . . . . Cap Poly(A)-tall proteins to facilitate Mature | transcription of specific genes . AAA In each cell type. RNA c. Open chromatin structure, favorable for transcription, is formed by protein action. C ytoplasm d. Alternative promoters are utilized in different cell types WAAA to produce different pre-mRNA molecules. e. Methylation of DNA inhibits transcription. Polypeptide 9 Post-translation a. Polypeptides are processed and modified in the Golgi body before transportation out Of C6“. Functiona' b. Regulatory molecules bind protein k to a polypeptide to alter its function. c. Protein stability is regulated. 6 mRNA processing a. Capping of the 5’ end, polyadenylation of the 3' end, and intron splicing mod'rfy pre—mRNA. b. Alternative capping and polyadenylation sites can be used in different cell types. c. Alternative splicing produces different mature mRNA molecules from some cell types. d. RNA editing modifies the base sequences of mRNA. 6 Regulation of mature mRNA a. Translational regulatory proteins bind mature mRNA to delay translation initiation. b. Small RNAs regulate the stability or translation of mRNA. c. Transport of mature mRNA to cytoplasm is regulated. d. RNA stability is regulated. 0 Translation Masking of mRNA delays or prevents translation.