Chapter 26


Retroviridae: General Features

• Midsized viruses with an enveloped capsid containing two copies of a single-stranded (+) RNA genome, transfer RNA (tRNA), reverse transcriptase, integrase, and protease.

• Two human pathogens—human immunodeficiency virus (HIV) and human T lymphotropic virus (HTLV)—are retroviruses.

Retroviral genes

1. All retroviral genomes contain three genes—gag, pol, and env—and are flanked by long-terminal repeats (Table 26-1).

2. Complex retroviruses, such as HIV, have several other genes encoding auxiliary and regulatory proteins (e.g., nef, tat, and rev)

Key HIV proteins (Fig. 26-1)


1. Attachment and fusion

2. Formation of HIV provirus

3. Viral messenger RNA (mRNA) and genome replication

4. Assembly

Genetic variation

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Jun 18, 2016 | Posted by in IMMUNOLOGY | Comments Off on Retroviruses

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