BIOL 200 Lecture 10: Lecture 10 - LTR Retrotransposons, LINEs and SINEs
Document Summary
Lecture 10 - ltr retrotransposons, lines and sines. Cut and paste: dna transposons, transposition. Reverse transcription: reverse transcriptase can use an rna template to make a. Retrotransposons are transcribed into an rna molecule, which is then reverse-transcribed into double stranded dna. Dna: viral dsdna is transported to the nucleus and. Integrated viral dna (provirus) is transcribed by host-cell"s machinery. Host cell machinery translates viral mrnas into glycoproteins and nucleocapsid proteins: progeny virions assemble and are released by budding. Same structure as a proviral form of a retrovirus: long direct terminal repeats (250-600bp) anking the central protein-coding region. Retroviral orfs encode polyproteins: gag -> capsid, pol -> protease, reverse transcriptase, integrase. Pol is a polyprotein; 3 proteins are translated together but they are eventually cleaved, forming separate polypeptides: env -> envelope. What came rst: ltr-retrotansposons (trapped in host) or retroviruses (infectious): more likely that ltr gained an env gene that lead to an infectious particle.
