BK viral enhancer element and a human cellular homolog

Area of Science:

• Virology
• Molecular Biology
• Evolutionary Biology

Background:

• Simian virus 40 (SV40) and human BK virus (BKV) are closely related primate papovaviruses.
• Tandem repeat sequences adjacent to replication origins show extensive divergence between SV40 and BKV.
• These divergent regions in SV40 are known to enhance early gene expression.

Purpose of the Study:

• To investigate the enhancer function of the analogous repeated region in BK virus (BKV).
• To explore the evolutionary relationship between viral enhancer sequences and host cell sequences.

Main Methods:

• Comparative sequence analysis of SV40 and BKV.
• Functional analysis of BKV tandem repeats for enhancer activity.
• Investigation of a homologous human genomic locus for enhancer function.

Main Results:

• The analogous repeated region in BKV demonstrates enhancer function for early gene expression, similar to SV40.
• Sequence dissimilarity between BKV and SV40 enhancers suggests independent acquisition post-divergence.
• A human genomic locus homologous to BKV repeats functions as a low-level enhancer in mammalian cells.

Conclusions:

• Viral enhancer sequences in papovaviruses like SV40 and BKV possess functional similarity despite sequence divergence.
• The data support the hypothesis that viral enhancer elements may have evolutionary origins related to host cell DNA sequences.