The HIV Genome

HIV fundamentals

To understand how HIVDR develops and how ARV drugs interfere with the HIV life cycle, it is important to have a good understanding of the HIV genome.

A genome can be compared to a story book. Found within the story book (genome) are letters of the alphabet (nucleotide bases) that make up many different words (amino acids), which make sense together in a sentence (protein). Variations and combinations of sentences make up one chapter (a single gene), and when the chapters are put together, they make up the story book (genome).

Component
of DNA/RNA
Analogy to
the recipe book
Example
Nucleotides (also
known as ‘bases’): A, C,T,G or U
Letters used to write
words
C a t e h m a t h e c a t m n o
Amino acids (coded for
by a group of 3 bases called a CODON)
20 wordsCat, mat, the, on sat
ProteinSentenceThe cat sat on the
mat.
GeneChapterThe cat sat on the
mat. It was a beautiful sunny day out….
Genome of the human,
virus, etc.
Complete book-

There are two types of nucleic acids: RNA and DNA. They are made from the same nucleotides, but have different functions in the body. HIV is an RNA virus, meaning its HIV has an RNA genome and all the RNA codes for the proteins needed by the virus to function.

  • There are 21 amino acids (AA) in total.
  • Strings of different AAs make up a protein. An enzyme is an example of a protein.
  • Codons consist of three different nucleotides. Each codon encodes for one specific AA.
  • Changes in a codon is known as a mutation, which may cause the encoding of a different AA.
  • This is the mechanism that the HIV uses to develop resistance and escape the action of the ARVs

HIV lifecycle

It is fundamental to understand the reproductive life cycle of HIV. There are seven key steps that use enzymes (special proteins) to allow HIV to multiply. The figure below demonstrates how HIV binds with CD4 cell receptors, and fuses with the host cell of an HIV patient.

HIV lifecycle