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作者从受乙型肝炎病毒(HBV)感染的黑猩猩肝中提取了RNA,亦从含有HBV DNA的大鼠细胞系中制备了RNA。作者用S1保护实验、核酸外切酶Ⅶ实验和引物延长实验等,均证明HBV的S(表面抗原)基因转录体的5＇端位于S基因编码区上游185个核苷酸处(即在HBV核苷酸1255位处)。在此,S转录体起始位点的上游约30个核苷酸处是假设的启动子区,此区被切割(用限制性内切酶Fnu4H)即可使转录起始消失。如果在其更上游220个核苷酸处(即在HBV核苷酸1004位处)被切割(用BamHI),并不影响转录的起始。这证明S基因转录起始所需的所有顺序均存在于S基因主要起始位点之前
The authors extracted RNA from chimpanzee liver infected with Hepatitis B virus (HBV) and also prepared RNA from a rat cell line containing HBV DNA. The authors used the S1 protection experiment, the exonuclease VII experiment and the primer extension experiment to prove that the 5 ’end of the HBV S (surface antigen) gene transcript is located 185 nucleotides upstream of the S gene coding region At nucleotide position 1255). Here, a putative promoter region of about 30 nucleotides upstream of the start site of the S transcript is cleaved (by the restriction enzyme Fnu4H) to initiate the transcriptional inactivation. Cleavage (with BamHI) at its more upstream 220 nucleotides (ie at HBV nucleotide 1004) did not affect the initiation of transcription. This demonstrates that all the sequences required for the initiation of S gene transcription precede the main start site of the S gene