BioMG 3320 1st Edition Lecture 6Outline of Past LectureI. Recombinant DNAII. Cloning VectorsIII. PCRIV. DNA CloningV. Building a Physical Map of the GenomeOutline of Current LectureI. Chemistry of RNAII. RNA as Genetic MaterialIII. RNA Structures Current LectureI. Chemistry of RNA- Chemical structure of RNA is very similar to DNA but immense variety of types, forms and functions of RNA in cells: messenger RNA, ribosomal RNA, transfer RNA, others- DNA contains deoxyribose, bases A T C G and is usually double-stranded and constrainedin structure- RNA on the other hand contains ribose, bases A U C G, and is often single-stranded and less constrained in possible structure- The phosphodiester bond in RNA is not stable; it can be hydrolyzed at any time- Subtle differences in chemistry of RNA and DNA have profound structural consequences:-Extra hydroxyl group on sugar (ribose) = additional hydrogen bonding possible-Thymine replaced by uracil= wobble pairing These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.II. RNA as Genetic Material- Like DNA, RNA contains 4 nucleotides: similar potential for information- Unlike DNA, RNA is not stable due to hydrolysis in aqueous solution- No organism uses RNA as its genetic material- Many viruses use RNA as their genetic material including those that infect animals, plants and bacteria (many human pathogens)-Viral genomes are small so probability of hydrolyzing much smaller- RNA viruses need RNA-dependent RNA polymerase (RdRP). They can be single stranded (positive strand or negative strand) or double stranded. They have RNA replication - Retroviruses: their viral genome is RNA but goes through DNA stage-Single stranded RNA > DNA > Integrated DNA > Transcription of viral genes -Retrovirus fuses with eukaryotic cell, RNA goes through reverse transcription via reversetranscriptase to create viral DNA, which then goes to the nucleus and is integrated into the eukaryotic chromosome- Reverse Transcriptase converts RNA into DNA-mRNA always ends in A’s-mRNA template is annealed to a synthetic oligonucleotide primer-reverse transcriptase and dNTPs yield a complementary DNA strand-gives a DNA copy of RNA which can be used for recombinant DNA-key uses of reverse transcriptase: RT-PCR and recombinant DNA technology III. RNA Structures - Typical RNA structures include: single strands, bulges, internal loops and hairpins- Pseudoknots also occur which is when nonconsecutive nucleotides base pair with one another within a single strand-Helical regions forming back on themselves-This is the way RNA can wrap itself up to be more complex and ordered - Results of 3D folding causes a stable interaction - Ribozymes catalyze formation of RNA. Ribosomes are capable of partial self-replication- RNA World Hypothesis: This theory was proposed by Walter Gilbert and states that thereis a large population of RNA sequences and one RNA arises that can copy itself. This is the building block for getting life started. Today, the Central Dogma is believed to be the true theory (DNA > RNA > protein)- RNA is the only biomolecule that can function both as genetic material and as an enzyme- SELEX: systematic evolution of ligands by exponential enrichment; Take an enormous pool of RNA sequences and pick out one that has characteristic that you want (in this example, ATP-binding ability), add ATP coupled to resin into column, pour in RNA sequences, RNA sequences that do not bind ATP are discarded, RNA sequences that bindATP are amplified and enriched for ATP-binding function, and then this process is repeated. The result is RNA with specific characteristic that you were looking for - Non-Coding RNA (gene transcripts that do not code for protein)-Components of the translation machinery: ribosomal RNA, transfer RNA-RNAs involved in nucleic acid modification: small nuclear RNA, telomerase RNA, small nucleolar RNA-Regulatory RNAs: microRNA, large intergenic RNA, CRISPR