A comparison of in situ hybridization techniques for gene localization

Abstract

Three probes specific for ribosomal genes for their usefulness in hybridization in situ with human metaphase cells were compared. The probes used were: a bacterial plasmid, pMB9, containing a Xenopus ribosomal gene sequence coding for 18S and 28S ribosomal RNA and labeled enzymatically by nick-translation; complementary DNA prepared from mouse and human 28S ribosomal RNA with reverse transcriptase after enzymatic addition of 3''-poly(A) by Escherichia coli poly(A) polymerase; and complementary RNA transcribed enzymatically from the Xenopus ribosomal gene plasmid by E. coli RNA polymerase. Recombinant plasmids should be extremely useful for the localization of sequences reiterated at low frequencies as suitable plamids become available.