1. Molecular Basis for Relationship between Genotype and Phenotype DNA RNA protein genotype function organism phenotype DNA sequence amino acid sequence transcription translation

2. State of phosphorylation of CTD determines the type of proteins that can associate with the CTD (thus defining cotranscriptional process). 5’ end of pre-mRNA is capped with 7-methylguanosine. This protects the transcript from degradation; capping is also necessary for translation of mature mRNA. Cotranscriptional Processing of RNA Refer to Figure 8-13 from Introduction to Genetic Analysis, Griffiths et al., 2015.

3. Cotranscriptional Processing 3’ end of the transcript typically contains AAUAAA or AUUAAA. This sequence is recognized by an enzyme that cleaves the newly synthesized transcript ~20 nucleotides downstream. At the 3’ end, a poly(A) tail consisting of 150 - 200 adenine nucleotides is added. Polyadenylation is another characteristic of transcription in eukaryotes.

4. Different mRNA can be produced; different  -tropomyosin can be produced. Alternative splicing is a mechanism for gene regulation. Gene product can be different in different cell types and at different stages of development. Complex Patterns of Eukaryotic RNA Splicing Refer to Figure 8-14 from Introduction to Genetic Analysis, Griffiths et al., 2015.

5. Intron Splicing: Conserved Sequences exons - coding sequences introns - noncoding sequences Small nuclear ribonucleoprotein particles (snRNPs) recognize consensus splice junction sequence of GU/AG. snRNPs are complexes of protein and small nuclear RNA (snRNA). Several snRNPs comprise a spliceosome. Spliceosome directs the removal of introns and joining of exons.

6. One end of conserved sequence attaches to conserved adenine in the intron. The “lariat” is released and adjacent exons are joined. Spliceosome interacts with CTD and attaches to pre-mRNA. snRNAs in spliceosomes direct alignment of the splice sites. Spliceosome Assembly and Function Refer to Figure 8-16 from Introduction to Genetic Analysis, Griffiths et al., 2015.

7. Reactions in Exon Splicing Refer to Figure 8-17 from Introduction to Genetic Analysis, Griffiths et al., 2015.

8. These self-splicing introns are an example of RNA that can catalyze a reaction. RNA molecules can act somewhat like enzymes (ribozymes). In the protozoan Tetrahymena, the primary transcript of an rRNA can excise a 413-nucleotide intron from itself. Self-Splicing Reaction Refer to Figure 8-18 from Introduction to Genetic Analysis, Griffiths et al., 2015.

9. Colinearity of Gene and Protein DNA RNA protein genotype function organism phenotype DNA sequence amino acid sequence transcription translation

10. Molecular Basis for Relationship between Genotype and Phenotype DNA RNA protein genotype function organism phenotype DNA sequence amino acid sequence transcription translation

11. Anticodon of a tRNA molecule recognizes and pairs with an mRNA codon. tRNA contains modified bases: pseudouridine, methylguanosine, dimethylguanosine, methylinosine, dihydrouridine. tRNA Refer to Figure 9-6 from Introduction to Genetic Analysis, Griffiths et al., 2015.

12. Genetic Code

13. Aminoacyl-tRNA Synthetase Attaches Amino Acid to tRNA Aminoacyl-tRNA synthetase catalyzes the formation of “charged” tRNA. There is an aminoacyl- tRNA synthetase for each amino acid. The carboxyl end of an amino acid is attached to the 3’ end of the tRNA. Refer to Figure 9-7 from Introduction to Genetic Analysis, Griffiths et al., 2015.

14. Wobble Position Some tRNA molecules can recognize and pair with more than one specific codon. Base-pairing between the 3’ base of a codon and 5’ base of an anticodon is not always exact. Refer to Figure 9-9 from Introduction to Genetic Analysis, Griffiths et al., 2015.