http://www.ebsi.co.kr/ebs/lms/lmsx/retrieveSbjtDtl.ebs?sbjtId=S20180001029 ================================================================================ Operon: unit of transcription at one time Operon = promoter, operator, structural gene "Regulatory gene" is not included into operon ================================================================================ Promoter is the DNA place where RNA polymerase is attached ================================================================================ "Regulatory gene" is always activated, so that part is always "transcripted" and "translated", result in "regulatory protein" ================================================================================ "Regulatory protein" is attached into "operator" in DNA ================================================================================ Let's have practical example E_coli has "lac operon" If E_coli has glucose: energy=E_coli_uses(glucose) If (E_coli has no_glucose) and (E_coli has Lactose): lactase=E_coli_produces_lactase() energy=E_coli_uses(Lactose,lactase) ================================================================================ Variable_condition=[lacose_exists,lactose_not_exists] ret1=E_coli_activates_lactase_gene(Variable_condition[0]) ret1: True ret2=E_coli_activates_lactase_gene(Variable_condition[1]) ret1: False ================================================================================ Situation: glucose mRNA=transcription(regulatory_gene) regulatory_protein=translation(mRNA) attach_operator_and_promoter(regulatory_protein) ret=is_possible_to_combine(promoter,RNA_polymerase) # False due to "attached regulatory protein" ret1=is_possible_to_perform_transcription() # False, because RNA_polymerase can't be attached onto promoter ret2=is_lactase_created() # False Situation: no_glucose,Lactose mRNA=transcription(regulatory_gene) regulatory_protein=translation(mRNA) manipulated_regulatory_protein=combine(regulatory_protein,Lactose) ret=is_it_possible_regulartory_protein_to_attach_to_operator(manipulated_regulatory_protein) # False, because manipulated_regulatory_protein has different protein structure combine(RNA_polymerase,promoter) RNA=transcription(structural_gene) lactase=translation(RNA) ================================================================================ Mutant on the promoter: ret=is_it_possible_for_RNA_polymerase_to_attatch_to_promoter() # False Situation (no_Lactose) or (Lactose): ret1=transcription_on_structural_gene?() # False Mutant on the operator: ret=regulatory_protein_can_combine_to_operator?() # False ret1=Structural_gene_always_activates?() # True ================================================================================ Regulation on gene expression of Eukaryota Chromosome is densely wrapped around histone protein RNA polymerase is difficult to access to DNA So, chromosome should be losen a bit (chromatin decondensated) RNA polymerase + many transcription factors can be attached to promoter Near transcription factor, near transcription-factor combine location in DNA Far transcription factor, far transcription-factor combine location in DNA ================================================================================ After RNA polymerase + many transcription factors are attached to promoter, DNA becomes curved This is called "transcription starting complex" ================================================================================ After forming transcription starting complex, transciption occurs ================================================================================ Transcriptor_factors: protein ================================================================================ * Raw RNA = Axon + Intron Intron: is transcripted but is not translated Intron doesn't have information for amino acid When there are axon_1, axon_2, axon_3, possible combination: axon_1, axon_2, axon_3 axon_1, axon_3 axon_2, axon_3 ... * Processed RNA which can be out via nucleus pore ================================================================================ ================================================================================