Molecular cytochemistry of nucleic acids by gene technology and in situ hybridization and the advances in its application.

Molecular cytochemistry of nucleic acids by gene technology and the advances in its application are reviewed with special reference to in situ hybridization. Studies on the in situ hybridization of repetitive and unique DNA sequences, messenger RNA, and viral genomes are outlined. A brief survey of the methods employed for labeling DNA and RNA probes with high specific radioactivity or nonradioactive markers and sensitive detection systems are given. The data of our own studies on the detection of Y chromosome by in situ hybridization with biotin-labeled DNA probes, molecular cloning of proviral DNA of a retrovirus produced in a human lymphoblastoid cell line, and in situ detection of gene expression of the molecularly cloned proviral DNA in transfected cells are also presented. The gene expression was detected in several percent of the transfected cells by indirect immunoperoxidase staining of viral proteins as well as by in situ hybridization of viral RNA with a [32P] -labeled probe and with a biotin-labeled probe.