Table 1. Nucleotide sequences of the primers used in this study.

Target regions	Stages of PCR	Primer sequences	Expected Sizes of PCR products
Pre-S
	First	PSFo: 5′-ttgcgggtcaccttattcttg-3′
		PSRo: 5′- agcaggggtcctaggagtc-3	598 bp
	Second	PSFi: 5′-ggaacaagagctacagc-3′
		PSRi: 5′- ctgatgcgatgttctccatgtt-3′	558 bp
Precore/X
	First	PCFo: 5′- gccttctcatctgccggtcc-3′
		PCRo: 5′- gtatggtgaggtgaacaatg-3′	505 bp
	Second	PCFi: 5′- cataagaggactcttggactcc-3′
		PCRi: 5′- aaagaattcagaaggcaaaaaaga-3′	320 bp
Virus-Host junction (Alu-PCR)
	First	Alu3: 5′- aUUaacccUcacUaaagccUcgaUagaUYRYRccaYUgcac-3′
		Alu5: 5′ – cagUgccaagUgUUUgcUgacgccaaagUgcUgggaUUa-3
	Second	Tag3: 5′- attaaccctcactaaagcctcg-3′
		Tag5: 5′- caagtgtttgctgacgccaaag-3′

Y = c+t; R = a+g, U = dUTP; In Alu-PCR, four sets of PCR were performed using Alu3/PCFo, Alu3/PCRo, Alu5/PCFo, and Alu5/PCRo as the first stage PCR primers. Subsequently, uracil DNA glycosylase was added to break the DNA strands at apurinic dUTP sites. Finally, Tag3/PCFi, Tag3/PCRi, Tag5/PCFi, and Tag5/PCRi were used respectively for the second stage PCR.