Hepatitis B virus preS1 deletion is related to viral replication increase and disease progression

Figure 1 Primer and probe positions designed to detect hepatitis B virus pre-S1 gene deletion sequence variants at the start codon of preS1. Four types of probes for detection of wild type and three deletion types (15-bp, 18-bp and 21-bp deletions) were used to screen the deletion variants. The arrows indicate the primer positions. The underlining indicates the probe positions. The numbers indicate the nucleotide position on the S gene sequence. The boldface bases indicate different bases from those of the consensus sequence. The amino acid sequence is shown as the one-letter amino acid symbol. WT: Wild type; WT’: W4P mutation; 15, 18, 21bp Del: 15, 18, 21 base pair deletion.