P1 and cosmid clones define the organization of 280 kb of the mouse H-2 complex containing the Cps-1 and Hsp70 loci

A 280 kilobase (kb) contig was isolated from mouse genomic P1 and cosmid libraries, using as probes human cDNA and genomic DNA fragments that map in the interval between the second component of complement and tumor necrosis factor genes of the HLA complex. The clone contig demonstrates synteny of eleven mouse genes that are homologous to genes initially mapped within the human major histocompatibility complex. These include the mouse homologs of BAT2 (HLA-B-associated transcript 2) through BAT9 and also three HSP70-related genes. Five P1 clones form a contig of 240 kb that spans from BAT9 through BAT3. Twelve cosmid clones are arranged in three contigs that confirm most of the structure of the P1 contig and link the mouse BAT3 homolog to the BAT2 homolog approximately 15 kb farther telomeric. Polymorphic DNA markers within the cloned region were used to map the cleft palate susceptibility-1 (Cps-1) locus to the interval between Hsp70.1 and BAT6 (valyl-tRNA synthetase). This refines the location of the Cps-1 locus to a 45 kb region contained in the H2-124 P1 insert.

Association between alleles of the transforming growth factor-alpha locus and the occurrence of cleft lip

DNA samples from 100 patients with cleft lip with or without cleft palate (CL/P) were compared with those of 98 unaffected control individuals with respect to transforming growth factor alpha (TGFA) genotypes. Among the Caucasians in this population (83 CL/P, 84 controls), there was a significant difference in the restriction fragment length polymorphisms (RFLPs) observed after digestion with TaqI (chi 2 = 4.68, P = 0.03). The frequency of the C2 allele in the Caucasian CL/P population was 0.169, whereas that in the control group was 0.089. When the data for Caucasians, African-Americans, and Asians were examined jointly, the chi 2 value for the pooled sample was 5.08 (P = 0.02). This confirms the hypothesis of Ardinger et al. [1989, Am J Hum Genet, 45:348-353] that TFGA itself or a closely linked gene contributes to the development of CL/P in humans.

Isolation, chromosomal mapping, and expression of the mouse tyrosinase gene

Using a human tyrosinase cDNA probe, we have isolated mouse tyrosinase genomic clones and used them to map the mouse tyrosinase locus and to analyze the promoter sequence of the tyrosinase gene. Southern blot analyses of DNA from somatic cell hybrids, interspecies backcross mice, and albino deletion mice have revealed that the locus for mouse tyrosinase resides at or near the albino locus on mouse chromosome 7. There were three TATA-elements, but only one CAT-element, and the CAT-element appeared to be paired with the third TATA-element, located at the position farthest upstream. Mouse tyrosinase mRNA is approximately 2.4 Kb in size. The amount of tyrosinase mRNA reflects the levels of tyrosinase activity in normal melanocytes and Cloudman S-91 melanoma cell line.

Establishment and partial characterization of SV40 virus-immortalized hepatocyte lines of normal and lethal mutant mice carrying a deletion on chromosome 7

Deletions in chromosome 7 of the mouse have been shown to cause failure of expression of various hepatocyte-specific genes in newborn deletion homozygotes, including the gene encoding tyrosine amino transferase (TAT) (EC 2.6.1.5) (Gluecksohn-Waelsch, 1979). Primary liver cultures of newborn albino deletion mutant mice (c14CoS/c14CoS) and of phenotypically normal mice (c14CoS/cch or cch/cch) were infected with SV40 virus and multiplying hepatocytes selected in arginine-deficient medium containing epidermal growth factor (EGF), insulin, and hydrocortisone (HC). Resulting normal (NMH-ch) and mutant (NMH-m14) hepatocyte lines expressing integrated viral transforming sequences did not senesce, they multiplied autonomously of EGF in medium with insulin plus HC, and they retained hepatocyte-specific functions. Both lines synthesized arginine and contained albumin and alpha-fetoprotein (AFP) mRNAs. TAT-specific mRNA was detected in normal but not in mutant hepatocyte lines. A fragment of the mouse tyrosinase gene, known to map at the albino locus (c) within the region deleted in the c14CoS mutant, hybridized with a 2.5 kb EcoRI fragment of normal NMH-ch DNA, whereas this fragment was undetectable in mutant NMH-m14 DNA. These immortalized hepatocyte lines reflect important properties of normal and mutant liver tissues from which they were derived. The deletion mutant mouse cell lines may be useful for complementation studies involving sequences corresponding to the deletions that encode regulatory gene(s) involved in the control of inducible expression of certain hepatocyte-specific genes such as TAT.

The structure of the mouse lymphocyte pore-forming protein perforin

Purified murine lymphocyte pore-forming protein (PFP or perforin) was partially sequenced. Oligonucleotides synthesized on the basis of this sequence information were used to screen a murine cytotoxic T lymphocyte (CTL) cDNA library. Seven clones were obtained, two of which were sequenced, providing full-length sequence information on PFP. Murine PFP (534 a.a.) is 68% identical to human PFP. Hydropathic analysis revealed a predominantly hydrophilic protein with some hydrophobic domains, including a region (a.a. 191-251) that could contain putative membrane-spanning domains. PFP is approx. 20% identical to human C7, C8 and C9 within a region encompassing 270 a.a., confirming previous immunological cross-reactivity studies. Northern blot analysis showed that expression of PFP but not of a serine esterase transcript is enhanced in a CTL line by antigen receptor-stimulation. Southern blot analysis of mouse genomic DNA indicated that PFP is encoded as a single-copy gene with the coding region contained within 10 kilobases of genomic DNA.

Sequence analysis of mouse tyrosinase cDNA and the effect of melanotropin on its gene expression

Using human tyrosinase cDNA as a probe, a mouse tyrosinase cDNA clone representing approximately 75% of the tyrosinase coding region and a mouse genomic clone which includes the tyrosinase 5' coding sequences were isolated: nucleotide and deduced amino acid sequence of the mouse tyrosinase gene were determined from these clones. The predicted amino acid sequence revealed that the mouse tyrosinase is composed of 533 amino acids with a molecular weight of 60,536. The deduced protein contains 6 potential N-glycosylation sites, two cysteine- and two histidine-rich regions which may serve as copper-binding sites, a potential signal and transmembrane sequences. The mouse and human tyrosinase nucleotide and deduced amino acid sequences are approximately 81% homologous. The level of mouse tyrosinase mRNA was elevated after stimulation of Cloudman S-91 melanoma cells with melanotropin and isobutylmethylxanthine and the level of transcript reflected that of tyrosinase activity and melanin content in the cells.

A melanocyte-specific complementary DNA clone whose expression is inducible by melanotropin and isobutylmethyl xanthine

Two groups of cDNA clones were isolated by screening a lambda gt11 cDNA library of normal human melanocytes with antityrosinase antibodies: one group of 13 was related to the human tyrosinase gene. The properties of the other group of three cDNA clones was investigated by the use of a representative clone, Pmel 17-1. The cDNA hybridized to an mRNA species of approximately 2600 bases from human and murine melanocytes. The transcript of Pmel 17-1 (17-1 mRNA) was expressed preferentially in melanocytes and its abundance paralleled the melanin content. The expression of Pmel 17-1 mRNA increased after stimulation of human and murine melanoma cells with agents that increase the levels of melanization. Immunocompetition assays with monoclonal antibodies to gp75, a known pigmentation-associated antigen of melanocytes, suggested that Pmel 17-1 encodes a 75,000 Mr glycoprotein that is highly abundant in melanotic cells and shares some immunological homology with tyrosinase. The gene for Pmel 17-1 did not map at or near the c-albino locus in mice. The cDNA of Pmel 17-1 detected a single hybridizing restriction fragment in both human and murine DNA, indicating that the gene has been conserved between these two species and exists as a single gene in each.

Isolation and sequence of a cDNA clone for human tyrosinase that maps at the mouse c-albino locus

Screening of a lambda gt11 human melanocyte cDNA library with antibodies against hamster tyrosinase (monophenol, L-dopa:oxygen oxidoreductase, EC 1.14.18.1) resulted in the isolation of 16 clones. The cDNA inserts from 13 of the 16 clones cross-hybridized with each other, indicating that they were from related mRNA species. One of the cDNA clones, Pmel34, detected one mRNA species with an approximate length of 2.4 kilobases that was expressed preferentially in normal and malignant melanocytes but not in other cell types. The amino acid sequence deduced from the nucleotide sequence showed that the putative human tyrosinase is composed of 548 amino acids with a molecular weight of 62,610. The deduced protein contains glycosylation sites and histidine-rich sites that could be used for copper binding. Southern blot analysis of DNA derived from newborn mice carrying lethal albino deletion mutations revealed that Pmel34 maps near or at the c-albino locus, the position of the structural gene for tyrosinase.