Nucleotide sequence of the BK virus DNA segment encoding small t antigen

Area of Science:

• Molecular Biology
• Virology
• Genetics

Background:

• BK virus is a human polyomavirus.
• The early genes of polyomaviruses, including BK virus and simian virus 40 (SV40), encode tumor antigens (T antigens).
• The small t protein's function and sequence are less understood compared to the large T protein.

Purpose of the Study:

• To determine the nucleotide sequence of the BK virus genome encoding the small t protein.
• To identify the open reading frame (ORF) for the small t protein.
• To compare the BK virus small t protein sequence with that of SV40 to understand evolutionary relationships and conserved functional regions.

Main Methods:

• DNA sequencing of the BK virus genome.
• Bioinformatic analysis to identify ORFs and termination codons.
• Sequence alignment and homology comparison with SV40.

Main Results:

• A single ORF coding for a 172-amino acid polypeptide, the putative BK virus small t protein, was identified.
• Multiple termination codons were found in all reading frames downstream of this ORF.
• Significant nucleotide and amino acid sequence homology was observed between BK virus and SV40, particularly in the region likely shared by BK virus small t and large T proteins.

Conclusions:

• The determined sequence provides the genetic basis for the BK virus small t protein.
• Sequence homology supports the evolutionary relatedness of BK virus and SV40.
• Conserved sequences highlight functionally important amino acid regions within early papovavirus genes, likely involved in T antigen functions.