| [ Summary ] |
The HCV genome exhibits significant genetic heterogeneity, as a result of mutations that occur during viral replication, and the most heterogeneous domains exist within the E2 region, which are referred to as HVRs. The heterogeneity of these regions is thought to contribute to the establishment of chronic HCV infection due to the selection of mutants that escape from the immune system of the host. It has been reported that the heterogeneity of HVR1 shows a broad distribution even in the early stage of chronic HCV infection and that the degree of this heterogeneity has no correlation with the disease stage. However, with the region from the core to E1, the degree of genomic heterogeneity is reportedly related to the progression of liver disease. In contrast to these variable regions of the HCV genome, the existence of an exceptionally conserved novel sequence downstream from a poly (U) stretch has recently been reported. The newly recognized 98-nucleotide sequence is considered to be the 3' tail of the HCV genome and to play an important role in the initiation of genomic replication. |