The ADP/ATP translocator, a transmembrane protein of the mitochondrial inner membrane, is coded in Saccharomyces cerevisiae by the nuclear gene PET9. DNA sequence analysis of the PE19 gene showed that it encoded a protein of 309 amino acids which exhibited a high degree of homology with mitochondrial translocator proteins from other sources. This mitochondrial precursor, in contrast to many others, does not contain a transient presequence which has been shown to direct the posttranslational localization of proteins in the organelle. Gene fusions between the PET9 gene and the gene encoding I8-galactosidase (lacZ) were constructed to define the location of sequences necessary for the mitochondrial delivery of the ADP/ATP translocator protein in vivo. These studies reveal that the information to target the hybrid molecule to the mitochondria is present within the first 115 residues of the protein. In addition, these studies suggest that the "import information" of the amino-terminal region of the ADP/ATP translocator precursor is twofold. In addition to providing targeting function of the precursor to the organelle, these amino-terminal sequences act to prevent membrane-anchoring sequences located between residues 78 and 98 from stopping import at the outer mitochondrial membrane. These results are discussed in light of the function of distinct protein elements at the amino terminus of mitochondrially destined precursors in both organele delivery and correct membrane localization.

Ceruloplasmin (CP) is a copper-binding protein in vertebrate plasma. It is the product of an intragenic triplication and is composed of three homologous domains. Oligonucleotide probes constructed according to published amino acid sequences were used to identify cDNA clones encoding human CP. Two clones, CP-1 and CP-2, differed from each other by the presence or absence, respectively, of a deduced sequence of four amino acids. The two clones provided 81% of the sequence encoding CP. Comparison of the nucleotides of the three domains of the CP coding sequence revealed internal domain homology with identity of sequences ranging from 50.1% to 56%. The nucleotide sequence of CP-2 cDNA was compared to that of a homologous human protein, clotting factor VIII, and was found to be 48% identical overall. The CP gene was mapped to human chromosome 3 by somatic-cellhybrid analysis and to 3q25 by in situ hybridization; however, sites of hybridization to DNA on other chromosomal sites suggested additional CP-like DNA sequences in the human genome. A DNA polymorphism was detected with CP cDNA after endonuclease digestion of human DNA by Pst I. CP mRNA was detected in human liver, macrophages, and lymphocytes by in situ histohybridization.

The nucleotide sequence for an unusual, cloned human adenosine deaminase cDNA has been determined. Contained within a sequence of 1535 nucleotides is a coding sequence of 1089 nucleotides that encodes a protein of 40,762 daltons. The coding sequence is interrupted by a non-coding region containing 76 nucleotides. Both the 3' and 5' ends of this region have consensus sequences generally associated with splice sites. The 3' untranslated sequence contained 308 nucleotides, including a polyadenylation signal sequence 20 nucleotides from the end. The cloned cDNA appears to correspond to a nuclear mRNA precursor which contains a small intron.

The iron-binding protein transferrin has major roles in transporting, delivering, and sequestering ferric ions acquired by body tissues. Yet, during aging, serum transferrin levels decrease in humans. Likewise, in transgenic mice carrying chimeric human transferrin transgenes, liver expression of transferrin transgenes decreases with age. The aging regulation is due to decreased gene transcription. Electrophoretic mobility shift assays and antibody-recognition have revealed the binding of 5' regulatory elements of the human transferrin gene by three YY1 proteins, called YY1, YY1-a, and YY1-b, and an Sp1-a transcription factor. An age-related increase in YY1-a and YY1-b binding activities and a decrease in Sp1-like binding activity were shown. Since Sp1 is a positive transcription factor and YY1 can be a negative transcription factor, the alterations in their binding with age could cause the decreased transcription of the human transferrin transgene, and also the age-related decreased serum transferrin levels in humans.

The structure of human adenosine deaminase mRNA from normal and mutant lymphoblasts was examined by sequence analysis of a cDNA for normal mRNA and electrophoretic analyses of DNA fragments generated by S1 endonuclease cleavage of mRNA-cDNA hybrids. The 1,533-base sequence of the cloned cDNA represents the complete mRNA sequence with the possible exception of some of the 5' untranslated region. S1 nuclease analyses of hybrids between cloned cDNA and normal adenosine deaminase mRNA confirmed that a 76-base sequence in a previously examined adenosine deaminase cDNA is an intron. S1 nuclease analyses of mRNAs from seven mutant cell lines demonstrated that four of the mutants, those in the GM-2471, GM-2756, GM-4258, and GM-2606 cells, contain small defects, such as single-base changes, that are not detectable by the S1 nuclease technique. Three of the mRNAs, those in GM-3043, GM-2294, and GM-2825A cells, do contain defects detectable with S1 nuclease. These defects differ from each other and have been mapped to specific regions of the mRNA. Some or all of these defective mRNAs are postulated to result from anomalous RNA processing.