Endogenous retrovirus HC2 pol fragments in the squirrel monkey: expression, evolution, and phylogeny

Area of Science:

• Genomics
• Molecular Biology
• Primate Research

Background:

• Human endogenous retroviruses (HERVs) are remnants of ancient retroviral infections integrated into the host genome.
• HC2 is an incomplete HERV provirus, lacking key genes for retroviral replication.
• Understanding HERV expression and evolution provides insights into host-pathogen interactions and genome evolution.

Purpose of the Study:

• To investigate the expression of the Human endogenous retrovirus HC2 (HC2) pol gene in the squirrel monkey (Saimiri sciureus).
• To analyze the sequence and evolutionary relationship of squirrel monkey HC2 pol gene sequences.
• To determine the evolutionary timeline of HC2 elements in primates.

Main Methods:

• Reverse transcription polymerase chain reaction (RT-PCR) was used to detect HC2 pol gene expression in various squirrel monkey tissues.
• RT-PCR products were cloned and sequenced for detailed analysis.
• Phylogenetic analysis was performed to compare squirrel monkey HC2 sequences with those from other primates and humans.

Main Results:

• The HC2 pol gene was expressed in specific squirrel monkey tissues, including cerebellum, liver, lung, and spleen.
• Sequenced HC2 pol gene fragments from squirrel monkeys exhibited 73.7-89.2% similarity to human HC2 pol genes.
• Phylogenetic analysis indicated that HC2 elements evolved before primate speciation and continued to evolve independently thereafter.

Conclusions:

• The HC2 pol gene is transcriptionally active in certain tissues of the squirrel monkey.
• Squirrel monkey HC2 pol sequences are evolutionarily related to human and other primate sequences.
• The findings suggest ancient origins and independent evolution of HERV elements across primate lineages.