Meltrin beta (ADAM19) gene: cloning, mapping, and analysis of the regulatory region.

Meltrin beta (ADAM19) is a member of the metalloprotease-disintegrin family. We report here chromosomal mapping of the mouse and rat meltrin beta genes and cloning and analysis of the mouse upstream regulatory regions. The meltrin beta transcript shows a spatially and temporally restricted expression pattern during morphogenesis, indicating that the actions of this membrane-bound protease are regulated, at least in part, at the transcriptional level. Analysis of the promoter revealed positive and negative regulatory regions upstream of the gene. The former includes a GC-box that appears to be a critical cis-element for activation of the promoter in muscle cells.

Spatio-temporally regulated expression of receptor tyrosine kinases, mRor1, mRor2, during mouse development: implications in development and function of the nervous system.

BACKGROUND: Drosophila neurospecific receptor tyrosine kinases (RTKs), Dror and Dnrk, as well as Ror1 and Ror2 RTKs, isolated from human neuroblastoma, have been identified as a structurally related novel family of RTKs (Ror-family RTKs). Thus far, little is known about the expression and function of mammalian Ror-family RTKs. RESULTS: We have identified murine Ror-family RTKs, mRor1 and mRor2. Both mRor1 and mRor2 genes are induced upon neuronal differentiation of P19EC cells. During neuronal differentiation in vitro, the expression of mRor2 is transiently induced, although that of mRor1 increases continuously. During embryogenesis, the mRor1 gene is expressed in the developing nervous system within restricted regions and in the developing lens epithelium. The expression of mRor1 is sustained in the nervous system and is also detected in non-neuronal tissues after birth. In contrast, the expression of mRor2 is detected mainly in the developing nervous system within broader regions and declines after birth. Possible relationships of mRor1 and mRor2 genes with previously identified mutants have also been examined. CONCLUSIONS: The developmental expressions of mRor1 and mRor2, in particular in the nervous system, are differentially regulated, reflecting their expression patterns in vitro. mRor1 and mRor2 may thus play differential roles during the development of the nervous system.

Cloning and genomic mapping of the mouse matrin 3 gene and its pseudogenes.

Matrin 3 forms a family of nuclear proteins together with NP220s. Using cDNA sequences encoding rat matrin 3 as a probe, we isolated genomic clones of mouse matrin 3 gene and its two pseudogenes. The genuine mouse matrin 3 gene has an exon covering the N-terminal one third of matrin 3 with a sequence 99% identical to rat matrin 3 cDNA. The gene was localized to Chromosome 18C by in situ hybridization and mapped at 3.6 cM distal to D18Mit117 and 2.2 cM proximal to D18Mit14 on mouse Chromosome 18 by interspecific backcross analysis. One pseudogene has an exon-like sequence covering the N-terminal half of matrin 3 that is interrupted by an unknown sequence. Reverse transcription polymerase chain reaction (RT-PCR) of RNA from mouse liver and brain using unique sequences of the genuine gene and the pseudogene confirmed the expression of only the former. The other pseudogene has a sequence only 80% identical to rat cDNA and is partially deleted and reversed. These pseudogenes were localized to Chromosome 4E2 and 8D2, respectively.

Genomic structures and chromosomal location of p91, a novel murine regulatory receptor family.

Recently, we found a novel murine cell-surface glycoprotein, designated as p91, expressed mainly in myeloid cells such as macrophages and mast cells. The molecule has six immunoglobulin-like extracellular domains, a transmembrane segment, and a cytoplasmic tail containing four immunoreceptor tyrosine-based inhibition motif (ITIM) or ITIM-like sequences, resembling the structural features of human killer-cell inhibitory receptors (KIR). Here we show that p91 comprises a polymorphic gene family, harboring one potent inhibitory-type p91 and at least two other p91 genes. Tyrosine-phosphorylated, but not nonphosphorylated, synthetic peptides matching the third ITIM and the fourth ITIM-like sequences, respectively, found in the cytoplasmic portion of p91A, the sole inhibitory-type p91, were associated with the tyrosine phosphatases, SHP-1 and SHP-2. In addition, the phosphotyrosyl peptide matching the third ITIM sequence also bound the inositol 5-phosphatase, SHIP. These results support the notion that p91A may function as an inhibitory cell-surface molecule against cell activation. The p91 genes were shown to be clustered in the proximal region of mouse chromosome 7, a syntenic position of human chromosome 19 where the genes for the KIR family are found. A human cDNA clone cross-hybridizing to a murine p91 probe was isolated from a human spleen cDNA library, and was found to code for a molecule quite similar to members of the immunoglobulin-like transcript (or ILT) family. The gene was found to be located on human chromosome 19q13.3-13.4. These results establish the existence of a novel set of potent regulatory receptors in mouse and man, similar but different from the KIR family.

Association of tyrosine phosphatases SHP-1 and SHP-2, inositol 5-phosphatase SHIP with gp49B1, and chromosomal assignment of the gene.

We have analyzed the molecules participating in the inhibitory function of gp49B1, a murine type I transmembrane glycoprotein expressed on mast cells and natural killer cells, as well as the chromosomal location of its gene. As assessed by SDS-polyacrylamide gel electrophoresis and immunoblot analysis, tyrosine-phosphorylated, but not nonphosphorylated, synthetic peptides matching each of the two immunoreceptor tyrosine-based inhibitory motif (ITIM)-like sequences found in the cytoplasmic portion of gp49B1 associated with the approximately 65-kDa tyrosine phosphatase SHP-1 and approximately 70-kDa SHP-2 derived from RBL-2H3 cells. In addition, the phosphotyrosyl peptide matching the second ITIM-like sequence also bound the approximately 145-kDa inositol polyphosphate 5-phosphatase SHIP. Thus, it has been strongly suggested that the inhibitory nature of gp49B involves the recruitment of SHP-1, SHP-2, and SHIP for the delivery of inhibitory signal to the cell interior upon phosphorylation of tyrosine residues in their ITIMs. The gp49B gene has been found to be in the juxtaposition of its cognate gene, gp49A. The gene pair was shown to locate in the B4 band of mouse chromosome 10. In this region, no conserved linkage homology to human chromosome 19, where the genes for killer cell inhibitory receptors are found, has been identified.

Chromosomal mapping of the gene encoding serotonin N-acetyltransferase to rat chromosome 10q32.3 and mouse chromosome 11E2.

Pineal melatonin is produced during the night. Its nocturnal increase regulates circadian rhythms and the photoperiodic reproductive response. Serotonin is acetylated to N-acetylserotonin by serotonin N-acetyltransferase (SNAT) and then methylated to form melatonin by hydroxyindole-O-methyltransferase (HIOMT). The rhythmicity of melatonin synthesis is regulated by the rhythmic activity of SNAT. Most laboratory mice do not have melatonin because of a genetic defect in the activity of SNAT and/or HIOMT. In a previous study using a recombinant inbred strain, we have found that the locus controlling pineal SNAT activity (Nat4) is located on mouse Chromosome 11. Recently, SNAT has been cloned in the rat. In the present study, the gene encoding SNAT was localized, using a rat cDNA fragment, on rat and mouse chromosomes by direct R-banding fluorescence in situ hybridization (FISH). In addition, using molecular linkage analysis with interspecific backcross mice, a gene encoding SNAT was mapped on a mouse chromosome. The gene encoding SNAT was localized to rat chromosome 10q32.3 and mouse Chromosome 11E2 by FISH. The molecular linkage analysis demonstrated that the gene encoding SNAT maps 1.5 cM distal to D11Mit11. The data suggest that Nat4 encodes SNAT. These chromosomal locations are in a region of conserved linkage homology between the two species.