Human DNA contains sequences homologous to the 5'-non-coding region of hepatitis C virus: characterization with restriction endonucleases reveals individual varieties

摘要

Objective To investigate a 272 base pair section of the 5' -non-coding region of genomic DNA from the peripheral blood monounuclear cells of healthy hepatitis virus C (HCV)-negative human subjects (not patients). Methods This sequence section bears interest because ① it harbors several potential methylation (Cp-rich) sites, and ② it represents the largest part of its internal ribosomal entry site. A pre-PCR digestion protocol was established making consistent use of four restriction endonucleases selected for certain features: Smal, XmaCl, Mspl, and Hpall are inhibited if methylation(s) are present at certain cytosines within their cutting sequences. Results The suspected HCV-specific sequence was found in the DNA of each subject tested. The pre-PCR digestion assay reveals individual differences in their pattern of methylation, which may be due to possible epigenetic phenomena. Conclusions The results provide formal proof that these HCV-specific sequences are contained in the genomic or extra chromosomal target DNA, and probably belong to a new class of endogenous sequences.