University:
The University Of Western Ontario
Course:
Biology 2290F | Scientific Method in Biology
Academic year:

2022
Views:

269

Pages:

2
Author:

Kyuwon J.

Reverse transcriptase (RT) ● Viral mutation is common due to this mechanisms ● Does not follow central dogma ● Antiviral drugs ○ AZT ■ No hydroxyl groups in thymine ■ Stops making viral DNA ● Goes reverse of central dogma system ● No proof reading ○ More mutation could be made in single transcription ○ Faster mutation rates ■ Yearly flu shots ● Enzymes ○ RNA dependent DNA polymerase ■ Converts RNA into DNA ○ Most retroviruses will use this mechanisms ○ Found in Eukaryotes (telomerase) ○ Found in retrotransposons ● Horizontal gene transfer ○ Retrotransposons ○ Telomerase maintains end of chromosome ● RT-PCR ○ Viral RNA => DNA PCR amplification ● cDNA- synthesis ○ Cloning eukaryotic gene ○ No introns buy copy it from mRNA ● Retroviral Vectors Challenges ● Off target effects ○ Usually in eukaryotic cells ○ Endogenous RT activity ■ LINE-1 retrotransposons ● RT replicate and insert into new locations ■ Telomerase (in RT) ● Maintain telomerase ● Can promote cancer if not regulated ○ Pathological implications ■ Instability ● Aberrant RT could cause insertional mutagenesis ● OFF on tumor suppressor genes ○ Autoimmune Disease ■ Reverse transcription in DNA ■ Lupus ● RT-PCR limitation ○ Priming problem ■ Random hexamers or gene specific primer needed ■ Introduce bias ■ Secondary RNA can block RT ○ Low Fidelity ■ cDNA error may affect downstream ● Evolutionary constraint ○ Speed / accuracy ■ Rapid synthesis over fidelity ■ Increase in mutation ○ Host defense evasion ■ Retrovirus HIV-1 exploits host machinery ■ Packinagin tRNA in primer ● Evade antiviral reaction ● CRISPR-based RT blockage ○ Cas13 targets viral RNA ○ RT template is not available for transcriptions anymore ● Allosteric RT inhibitors ○ RT dimerization is blocked ○ Compound similar to Dolutegravir