Identification of recombinant plasmids containing DNA sequences derived from the 3' end of ovine thyroglobulin mRNA

This paper describes the cloning in E. coli of several DNA copies of the 3' portion of ovine thyroglobulin mRNA. The cDNA clones were identified by in situ cloning hybridization to 32P-labelled thyroglobulin cDNA and by positive hybridization-translation assays. The longest thyroglobulin cDNA fragment cloned (psTg21A, 1670 bp), was shown by S1 nuclease mapping to be an unaltered copy of the thyroglobulin mRNA. psTg 21A overlapped with another cDNA fragment (psTg 11, 330 bp) containing the poly(dA)-tail and corresponding therefore to the 3' end of the mRNA. When aligned together the two clones represent more than 20% of the thyroglobulin mRNA length. Another cDNA fragment (psTg 15, 350 bp) was identified as an internal portion of the thyroglobulin mRNA sequence.