Retroviruses

Chapter 26


Retroviruses




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)




Replication





1. Attachment and fusion



2. Formation of HIV provirus



3. Viral messenger RNA (mRNA) and genome replication



4. Assembly



Genetic variation


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

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