BIOS 20175 Lecture Notes - Lecture 9: Guanine, Spliceosome, Adenine
Document Summary
Template strand/antisense strand: strand that is actually transcribed. Coding/sense strand: complementary to template strand and is identical to the transcript sequence. Upstream: toward 5" end of the coding strand. Downstream: toward 3" end of the coding strand. Transcription begins: core enzyme elongates processively along the transcription bubble, once determination signal is detected, by rho, pol falls off dna and the rna is released. Original rna from transcription needs to undergo modification: Splicing: removing the unnecessary information to reveal the protein coding segments. Splicing is mediated by a spliceosome, which assembles around each intron in real time (not preassembled) ~100 proteins many of which bind to snrnas to make 3 small nuclear ribonucleic particles (snrnps) snrnps recognize some nucleotide components and hydrogen bond to these sites. The ends of the intron are connected in a loop structure. The second reaction binds the two exons, to release the intron loop.