MICRB 201 Lecture Notes - Lecture 1: Rna Polymerase Iii, Open Reading Frame, Ribosomal Rna
Document Summary
Process of converting structural genes into rna transcrpts: could be mrna, trna, rrna, ssrna, etc. Enzyme: single dna dependent rna polymerase complex (fig. Mrna transcripts may be mono- or polycistronic (fig 7. 3a). like rrna and trna genes: however, polycistronic mrnas a(cid:396)e (cid:374)ot (cid:862)p(cid:396)o(cid:272)essed(cid:863): ea(cid:272)h ge(cid:374)e has its o(cid:449)(cid:374) ribosome-binding site (slide) transcription in eukaryotes. Rna pol iii makes trna instead of sigma factors, eukaryotes use transcription factors. Eukaryotic trna and rrna: arise by post-transcriptional processing. Eukaryotic mrna: also arise by post-transcriptional processing (prokaryotes mrnas do not; slide) Maturation of eukaryotic mrna initial mrna transcript (located in nucleus) is (cid:862)p(cid:396)o(cid:272)essed(cid:863) to fi(cid:374)al (cid:373) na p(cid:396)odu(cid:272)t (located in cytoplasm) Steps: additio(cid:374) of cap (cid:894)(cid:1011)(cid:373)eth(cid:455)l gua(cid:374)osi(cid:374)e(cid:895) to (cid:1009)(cid:859) e(cid:374)d of (cid:373) na, removal of introns and splicing of exons by the splicesosome. Exon (expressed region)- present in final mrna product. Intron (interveining region) - not present in final mrna product. 3. additio(cid:374) of pol(cid:455) (cid:894)a(cid:895) tail to (cid:1007)(cid:859) e(cid:374)d of (cid:373) na.
