Question

Reverse Transcriptase (RTase) is an enzyme found in HIV. What is the function of this enzyme in HIV’s life-cycle? What are some uses of RTase for human applications?

Answer 1

Viral infections are mainly initiated by the fusion of viral and the cellular membranes which is caused by the interactions of the viral envelope glycoprotein with it's receptor mainly CD4 and co-receptor, usually CCR5 or CXCR4. These bindings helps in the process of membrane fusion. The membrane fusion allows the viral core, which contains the RT, into the cytoplasm of the cell. The RT has two main enzymatic activities, a DNA polymerase that can either copy a DNA or RNA template, and an RNase H that cleaves RNA only if the RNA is part od an RNA/DNA duplex.  

The two enzymatic functions of RT, polymerase and RNase H cooperates in order to convert the RNA into a double-stranded linear DNA. This takes place in the cytoplasm of the infected cell, after DNA synthesis has been completed, the result which is a linear double-stranded viral DNA is translocated to the nucleus where the viral DNA is inserted into the host genome by IN. This inserted DNA copy which is now called a provirus, is the source of both viral genomic and viral messenger RNAs, which are generated by the host DNA-dependent RNA polymerase.

USES of RTase for human applixcations.

The Self-replicating stretches of an eukaryotic genomes which are referred to as retrotransposons utilize reverse transcriptase in order to move from one position in the genome to another with the help of an RNA intermediate. Telomerase is a reverse transcriptase which is found in humans which carries its own RNA template, this RNA is utilized as a template for the process of DNA replication.