Effects of the gag region on genome stability: avian retroviral vectors that contain sequences from the Bryan strain of Rous sarcoma virus.
We have previously described replication-competent Schmidt Ruppin-A Rous sarcoma virus (RSV)-based retroviral vectors that can be used to deliver and express genes in avian cells. We have continued to modify the prototype vectors to develop a more versatile and efficient system. Substitution of the polymerase (pol) region from the Bryan high-titer RSV (BH-RSV) for the SR-A RSV pol region of these retroviral vectors causes these viruses to replicate more efficiently. We cloned the gag regions from two independent BH-RSV-transformed cell lines and tested whether substituting either of these gag regions would improve the replication and/or gene expression of the vectors. Chimeric vectors were constructed in which the gag region of the prototype vector (SR-A RSV) was replaced with the corresponding segment of BH-RSV gag in vectors that had either the original SR-A RSV pol or the BH-RSV pol region. All vectors contained the bacterial chloramphenicol acetyltransferase gene (CAT). The results indicate that different SR-A RSV and BH-RSV gag-pol chimeras can significantly affect the level of viral and CAT gene expression. The insertion of one of the BH-RSV gag regions, but not the other, gave rise to viruses with unstable genomes.
Federspiel
M J
MJ
ABL-Basic Research Program, NCI-Frederick Cancer Research and Development Center, Maryland 21702-1201.
Hughes
S H
SH
D000595:Amino Acid Sequence; D001358:Avian Sarcoma Viruses / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D005814:Genes, Viral; D015750:Genes, gag; D015751:Genes, pol; D005822:Genetic Vectors; D008969:Molecular Sequence Data