Study of salivary gland specific transcripts in Chironomus tentans by cDNA analysis

Preparative amounts of polyA-containing RNA were purified from isolated salivary glands from Chironomus tentans and used as a template for the synthesis of cDNA by AMV reverse transcriptase. The yield of cDNA corresponded to 8-14% of the input polyA RNA. Using the Alwine hybridization method (Alwine et al., 1977) it was shown that only a minor part of the cDNA hybridized to the 75S RNA band and that the major hybridization occurred to a hitherto unknown gland-specific polyA RNA transcript of 1.3 kb length. In addition, the cDNA hybridized to a gland-specific polyA-RNA transcript of 2 kb length. - The majority of the cDNA had a size of 0.4 or 0.7 kb in equal amounts. A Southern hybridization of the cDNA to an EcoRI digest of genomic DNA showed in addition to a very weak hybridization to the 40 kb band of the Balbiani ring genes, hybridization to several restriction fragments with sizes from 1.3 to 16 kb.