Characterization of a thyroid hormone-responsive gene from rat

We have isolated and characterized a rat gene coding for spot 14 mRNA: a hepatic product induced rapidly by thyroid hormone. This gene is present in a single copy/haploid genome, but encodes two mRNA species differing by 170 nucleotides in length. Through S1 nuclease analyses, the difference was mapped to the 3'-end of the mRNA with one species extending 170 nucleotides beyond the 3'-end of the other mRNA. The putative poly(A) addition signals AUUAAA and AAUAAA are found to precede the sites of polyadenylation in the shorter and longer mRNA, respectively. The mRNA codes for a protein of 150 amino acids with a molecular weight of 17,010. The protein-coding region is located closer to the 5'-end of the mRNA, leaving a relatively long 3'-untranslated region, which contains the only intron of 3,150 base pairs within the gene. At approximately 27 base pairs upstream from the start site of the mRNA, a sequence homologous to the TATA box, TAGAAAT , was found.     

The isolation and characterization of the murine T cell antigen receptor zeta chain gene

The T cell antigen receptor (TCR) is a multisubunit complex which has a dual function of antigen recognition and signal transduction. One of its invariant subunits, the zeta chain, has been shown to have a significant role in the expression and function of the TCR on the cell surface. The mouse and human zeta cDNAs share significant homologies to each other but are distinct from all of the previously characterized TCR components. We now report the isolation and structural analysis of the complete murine zeta gene. This gene spans at least 31 kilobases and divides into eight exons. The first exon, which is located at least 20 kilobases upstream from the second exon, codes for the 5'-untranslated region and most of the signal peptide. The second exon codes for the remainder of the signal peptide, the extracellular domain, the transmembrane domain, and the first three amino acids of the intracytoplasmic domain. Exons 3-7 encode the majority of the intracytoplasmic domain. The eight exon encodes the carboxyl-terminal 21 amino acids and the 3'-untranslated region. Four groups of mRNA initiation sites have been identified at approximately 140 base pairs upstream to the AUG codon. No TATA-like box has been detected. The gene is localized to the distal part of chromosome 1 in a linkage group highly conserved between man and mouse.     

Complementary deoxyribonucleic acid cloning of a novel transforming growth factor-beta messenger ribonucleic acid from chick embryo chondrocytes

Transforming growth factor beta 1 (TGF beta 1) has been purified and the mRNA cloned from a number of mammalian species including human, murine, bovine, porcine, and simian. Using a human TGF beta 1 cDNA probe, we have detected two distinct TGF beta RNAs in cultured primary chick embryo chondrocytes. One of these RNAs, migrating at about 1.7 kilobases, shows similarity to mammalian TGF beta 1. The second RNA, migrating at about 3 kilobases, is a novel TGF beta mRNA which we have named TGF beta 3. Clones corresponding to each of these RNAs were isolated from a cultured primary chick embryo chondrocyte cDNA library. Two cDNA clones for TGF beta 3, pTGFB-ChX17 and pTGFB-ChX25, contained a 39 nucleotide-long 5'-untranslated region, a 1236 nucleotide-long coding region, and a 911 nucleotide-long 3'-untranslated region. The predicted protein includes a signal peptide of 20-23 amino acids as in human TGF beta 1 and 2, and a precursor protein consisting of 412 amino acids, which can be cleaved at a lys-arg site to produce a 112 amino acid processed peptide containing nine cysteine residues in the same positions as in human TGF beta 1 and 2. At the nucleotide level, the processed coding region of TGF beta 3 shows 72% and 76% identity with the processed coding regions of human TGF beta 1 and TGF beta 2, respectively; at the amino acid level, TGF beta 3 shows 76% identity with TGF beta 1 and 79% identity with TGF beta 2.(ABSTRACT TRUNCATED AT 250 WORDS)