24. Transcription Results in an Unprocessed Message 5 ´ Cap added immediately to 5 ´ sequence, in this case ACATTTG Poly(A) tail added when sequence (5 AATAAA 3 ) is transcribed Heterogeneous nuclear RNA (hnRNA) also known as (aka) pre-mRNA or the primary transcript
40. Modular Nature of Upstream Region for Tissue-Specific Gene Expression Note that many different transcription factors can bind to one gene It is the set of proteins bound to a gene that determine the level and location of gene expression
61. Elongation Phosphorylation of Ser 2 recruits splicing factors Phosphorylation of Ser 5 recruits capping factors Other factors include TFIIS, P-TEFb, TAT-SF1
80. Self-excising group I & 2 introns 2 nucleophilic transesterification reactions 3 -OH guanosine on right side of intron is transferred to nucleotide at 5 end of intron Guanosine acts as cofactor "New" 3 -OH on left side of intron and phosphate group on 3 end of right side of intron interact leaving phosphate for ligation of exons 1 and 2
90. Types of Alternative Splicing (a) Alternative 5 ´ splice site (b) Alternative 3 ´ splice site (c) Skipping the variable alternative splice exon (d) Mutual exclusion of exons (e) Gender-specific splicing Alternative Poly(A) site Found in prostate cancer
93. Combinatorial Control Sex lethal binding results in stop codon being spliced out Functional transformer binding causes doublesex to be spliced in a female-specific fashion Stop codon remains Transformer not functional Male-specific doublesex
114. Negative Control Gene is expressed unless it is turned off by some regulatory molecule
115. Positive Control Gene only expressed if a regulatory molecule stimulates RNA synthesis
116. The lac Operon Prokaryotic genes do not have introns and exons make polycistronic mRNA - continuous transcripts that are composed of many genes.
122. Lac Operon Has 3 Operators All 3 operators must be bound for maximal repression . Repressor binding to 2 operators causes a DNA conformational change DNA bends away from the repressor forming a repression loop, preventing RNA polymerase access to the promoter
177. eIF4E Binding Proteins Compete for Binding with eIF4G eIF4E, A and G = eIF4F complex Sonenberg & Gingras, 1998
178. Control at initiation by numerous signal transduction pathways Many signal transduction pathways converge on eIF4E and phosphorylate it as well as other IF factors & ribosomal proteins Sonenberg & Gingras, 1998 eIF, Devers, 1999