Centra Dogma Primer

Structure of DNA and RNA• Nucleic acids made of nucleotides

• G, A, T/U, C• Ribose vs. deoxyribose• Template-dependent synthesis• Double helix• Complementary pairing, A = T, G = C

• Genetic code• Order of nucleotides specifies amino acids

DNA Double Helix

Central Dogma• Gene Expression• DNA makes RNA makes protein• DNA is transcribed into mRNA (nucleus) which is translated into protein (cytoplasm)

• Transcription of genes relies on the interaction of DNA binding proteins with the regulatory elements of the gene (promoter)• Some genes are activated in all cell types (housekeeping genes) and are regulated by ubiquitous promoters)• Some genes are activated in a restricted manner (tissue- specific genes) and are regulated by tissue-specific promoter and enhancer sequences

Central Dogma• Gene Expression • Pre-mRNA matures by splicing (the removal of

intervening sequences) and polyadenylation (the addition of poly A tracts to the 3’ end), processes believed to stabilize mRNA and assist in its transport to the cytoplasm

• Some mRNA transcripts are differentially spliced giving rise to proteins which may have different functions

Central Dogma• Gene Expression • Translation of mature mRNA occurs in the cytoplasm and involves the interaction with tRNA and rRNA complexes• Codons dictate where translation starts (AUG), stops (UAA, UAG, UGA), and which amino acids to incorporate into the growing polypeptide chain• Any mutations which have resulted in the addition or removal of nucleotides can alter the reading frame resulting in the translation of non- sense proteins or premature termination of translation.

Proteins and Biological Function• Proteins are end products of gene expression•“Limitless” variety possible

–n20

• Conformation determined by linear order of amino acids• Many functions

– Enzymes– Immunoglobulins– Structural proteins– Mobility– Many more

Play Videohttp://www.youtube.com/watch?v=J3HVVi2k2No

Videos• RNAi discovered • RNAi http://www.youtube.com/watch?v=DMlv8qexahU

• PCR http://www.youtube.com/watch?v=Xe27o3K_DbU

• rtPCR (funny) http://www.youtube.com/watch?v=qODtx25SXfo

http://www.youtube.com/watch?v=H5udFjWDM3E