Tag: molecular biology

Central dogma represents the sequential process of gene expression via four steps. Accordingly, the genetic information present in sequence of deoxyribonucleotides is transcribed into sequence of ribonucleotides in RNA which in turn serve as template to a polypeptide. The genetic information of DNA is self replicated via DNA replication where parent strand serves as template for synthesis of new DNA strands. Thus, transcription uses DNA strand template while translation uses RNA as template. But it is not always a linear process and can go upside down since reverse transcriptase enzyme synthesize DNA using RNA as template. It was first shown by Temin and Baltimore.

Tetracycline antibiotics are the protein inhibitors which inhibiting the binding of aminoacyl-tRNA to the mRNA-ribosome complex and prevents the translation (protein synthesis) as activated aminoacyl-tRNA bring amino acid in mRNA-ribosome complex.

Genetic information are transferred from nucleus to cytoplasm of cell through RNA. In eukaryotic cells, once precursor mRNA (pre-mRNA) has been transcribed from DNA, it is processed to mature mRNA. This removes its introns, non-coding sections, of the pre-mRNA. The mRNA is then exported from the nucleus to the cytoplasm, where it is bound to ribosomes and translated into its corresponding protein form with the help of tRNA. Ribonucleic acid (RNA) is a polymeric molecule. It is implicated in a varied sort of biological roles in coding, decoding, regulation, and expression of genes.

• Reverse transcriptase enzyme is an enzyme that is used to generate cDNA from RNA template through the reverse transcription process. This is seen in many retroviruses to replicate their genomes.
  
• DNA polymerase enzyme helps in DNA synthesis using DNA template, a process called replication.
  
• DNA ligase is used to join DNA fragments during DNA repair or its replication.
  

Retroviruses operate a central dogma reverse. RNA of these viruses first synthesis DNA through reverse transcriptase or RNA dependent DNA polymerase. This DNA synthesised on RNA template is called c-DNA or retroposons.

Reverse transcriptase is an RNA dependent DNA polymerase enzyme which means it uses RNA primers to synthesize DNA molecules. Reverse transcriptase enzyme used to generate complementary DNA (cDNA) from an RNA template by the process called reverse transcription. Retroviruses contain reverse transcriptase enzyme which converts their RNA genome into cDNA that can be incorporated into the host genome. 

c) Rous sarcoma virus (RSV) is a retrovirus causes sarcoma in chickens. The virus contains a reverse transcriptase which is a DNA polymerase that uses RNA as its template. This enzyme reverse transcribes RNA into cDNA and incorporation into the host genome.

HIV (Human Immunodeficiency Virus) is a retrovirus with a viral envelope, matrix proteins and core. The viral core consists of two single strands of RNA. Retroviruses containing RNA genome have reverse transcriptase enzyme that synthesizes a DNA copy (cDNA) of viral RNA. This cDNA can be introduced in the hosts' genome and allowed to replicate to form viral proteins. Influenza and vaccinia viruses are not retroviruses.