Löwer R, Löwer J, Tondera-Koch C, Kurth R
Paul-Ehrlich-Institut, Langen/Frankfurt, Germany.
Virology. 1993 Feb;192(2):501-11. doi: 10.1006/viro.1993.1066.
During the past decade, different types of endogenous retroviral sequences have been defined in the human genome usually by low stringency hybridization employing DNA probes of evolutionary conserved animal retrovirus genes. Although all human genomic loci sequenced were found to be defective or interspersed with stop codons, indirect evidence is accumulating that human endogenous retroviral loci are expressed at least in some instances. One example is the synthesis of retroviral particles in human teratocarcinoma cell lines observed by electron microscopy. To establish a link between virus expression and genomic loci we searched for retroviral RNA in human cellular mRNA populations using a generally applicable method. A tRNA-derived primer complementary to a putative retroviral primer binding site was extended by reverse transcription and this product was elongated with a homopolymeric stretch and amplified by PCR (R-U5 PCR). Cloning and sequencing of such products revealed that the endogenous retroviral loci HERV-H and HERV-K are expressed in those human teratocarcinoma cell lines which produce retroviral particles. The size distribution of four HERV-K mRNAs detected in Northern blots is reminiscent of the complex expression pattern seen with a number of exogenous retroviruses.
在过去十年中，人类基因组中不同类型的内源性逆转录病毒序列通常是通过使用进化保守的动物逆转录病毒基因的DNA探针进行低严格度杂交来定义的。尽管发现所有测序的人类基因组位点都有缺陷或散布着终止密码子，但越来越多的间接证据表明，人类内源性逆转录病毒位点至少在某些情况下会表达。一个例子是通过电子显微镜观察到人类畸胎瘤细胞系中逆转录病毒颗粒的合成。为了建立病毒表达与基因组位点之间的联系，我们使用一种通用方法在人类细胞mRNA群体中寻找逆转录病毒RNA。与假定的逆转录病毒引物结合位点互补的tRNA衍生引物通过逆转录进行延伸，该产物用同聚物延伸进行延长并通过PCR（R-U5 PCR）进行扩增。此类产物的克隆和测序表明，内源性逆转录病毒位点HERV-H和HERV-K在那些产生逆转录病毒颗粒的人类畸胎瘤细胞系中表达。在Northern印迹中检测到的四种HERV-K mRNA的大小分布让人联想到许多外源性逆转录病毒所呈现的复杂表达模式。
