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D R Beier

Publications and source records attributed to D R Beier.

At least 19 recordsLinked to original sources
PubMed2001

Characterization of the murine Lbx2 promoter, identification of the human homologue, and evaluation as a candidate for Alström syndrome.

The murine Lbx2 gene is a member of the ladybird family of homeobox genes, which is expressed in the developing urogenital system, eye, and brain. Using transgenic mice, we demonstrate that 9 kb of the 5' flanking region of mouse Lbx2 is able to direct expression of a reporter gene in a tissue-specific manner recapitulating the endogenous expression pattern. This regulatory region provides a novel reagent allowing for transgenic expression in the developing urogenital ridge. In addition, we describe the identification of the human homologue, LBX2. Comparison of the human LBX2 and mouse Lbx2 sequences upstream of the coding regions reveals sequence conservation suggesting conserved regulatory regions. Both the human LBX2 and the mouse Lbx2 genes have similar genomic structures and are composed of two exons separated by an intron. We mapped the mouse Lbx2 gene to 35 cM on chromosome 6 and the human LBX2 gene to a homologous region of chromosome 2p13. This is a candidate region for several inherited disorders, including Alström syndrome, a disorder that includes ocular, urogenital, and renal abnormalities. Given the expression pattern of Lbx2, the chromosomal location in humans, and the potential function of mammalian ladybird genes, we have begun to analyze patients with ocular disorders and those with Alström syndrome for mutations in LBX2. Although polymorphisms were identified, our results indicate that mutations in the coding region of LBX2 do not account for Alström syndrome in the six kindreds analyzed.

Amino Acid Sequence↗
PubMed2001

An Epstein-Barr-related herpesvirus from marmoset lymphomas.

Epstein-Barr virus (EBV) is implicated in the development of human B cell lymphomas and carcinomas. Although related oncogenic herpesviruses were believed to be endemic only in Old World primate species, we now find these viruses to be endemic in New World primates. We have isolated a transforming, EBV-related virus from spontaneous B cell lymphomas of common marmosets (Callithrix jacchus). Sequencing of two-thirds of the genome reveals considerable divergence from the genomes of EBV and Old World primate EBV-related viruses, including differences in genes important for virus-induced cell growth transformation and pathogenesis. DNA related to the C. jacchus herpesvirus is frequently detected in squirrel monkey peripheral blood lymphocytes, indicating that persistent infection with EBV-related viruses is prevalent in both New World primate families. Understanding how these more divergent EBV-related viruses achieve similar biologic outcomes in their natural host is likely to provide important insights into EBV infection, B cell growth transformation, and oncogenesis.

Amino Acid Sequence↗
PubMed2001

An integrated genetic and physical map of the 650-kb region containing the congenital polycystic kidney (cpk) locus on mouse chromosome 12.

Mice homozygous for the congenital polycystic kidney (cpk) mutation develop a rapidly progressive form of polycystic kidney disease. We report an integrated genetic and physical map of the 650-kb region containing the cpk locus and the exclusion of Rrm2 and Idb2 as candidate cpk genes. Our study establishes the requisite foundation for positional cloning of the cpk gene.

Animals↗
PubMed2000

Germline and somatic loss of function of the mouse cpk gene causes biliary ductal pathology that is genetically modulated.

The mouse cpk mutation is the most extensively characterized murine model of polycystic kidney disease (PKD) and closely resembles human autosomal recessive PKD (ARPKD), with the exception that B6-cpk/cpk homozygotes do not express the biliary ductal plate malformation (DPM) lesion. However, homozygous mutants from outcrosses to other strains, e.g. DBA/2J (D2), CD-1, BALB/c and Mus mus castaneus (CAST), express the DPM. The current study was designed: (i) to characterize the cpk-associated biliary disease in affected F(2) homozygotes from intercrosses with either CAST or D2; and (ii) to evaluate focal biliary cysts identified in heterozygotes from a D2-cpk congenic strain. We found that all F(2) cpk/cpk pups expressed both the typical renal cystic disease and the DPM. The DPM severity, assessed using semi-quantitative histopathological analysis, was markedly variable in these F(2) progeny. We found no correlation between the severity of the DPM and the renal cystic disease in either F(2) cohort. In addition, we identified focal cysts, apparently of biliary origin, in the livers of both aged D2-+/cpk and F(1) heterozygotes. Genetic analysis demonstrated loss of heterozygosity at the cpk interval and supports a loss-of-function model for biliary cysts. We conclude that the cpk allele contains an inactivating mutation which disrupts tubulo-epithelial differentiation in the kidney and biliary tract. Expression of the biliary lesion is modulated by genetic background, and the specific biliary phenotype is determined by whether loss of function of the cpk gene occurs as a germline or a somatic event.

Animals↗
PubMed2000

Structure and mapping of the mouse matrilin-3 gene (Matn3), a member of a gene family containing a U12-type AT-AC intron.

The gene for murine matrilin-3, an extracellular matrix protein present in cartilage, was isolated and further characterized. The gene spans 23.4 kb and comprises 8 exons; with one exception, this reflects the modular structure of the protein. The major and a minor transcription start site were determined by RNase protection assays to positions approximately 72 nt and 87 nt upstream of the ATG codon, respectively. The promoter contains a TATA-like box 32 bp upstream of the main transcription start as well as several potential binding sites for eukaryotic transcription factors. As in all known matrilin genes, the last intron, separating the exons coding for the coiled-coil domain, does not follow the GT-AG rule and belongs to the subgroup of introns having AT-AC at the ends that are spliced by the U12-type spliceosome. The mouse matrilin-3 gene does not contain hidden exon sequences coding for the second vWFA-like domain present in all other matrilins. The intron that could possibly contain such sequences instead shows 75% repetitive sequences, indicating an evolutionary process that has led to the loss of sequences coding for vWFA2. Single-strand conformation polymorphism analysis was used to map the Matn3 gene to the proximal end of Chr 12, linked to the genes Synd1, Apob, Dntb, and Kif3c.

Amino Acid Sequence↗
PubMed2000

Sequence-based analysis of mutagenized mice.

Treating mice with ethylnitrosourea (ENU) is an efficient means for mutagenizing spermatogonial cells, and this treatment has been proven effective in a variety of screens for both dominant and recessive mutations. However, a significant problem for this technology is that the efficiency of mutagenesis is assessed most often by the empiric determination of a per-locus mutation frequency by using the specific locus test, which is expensive, time-consuming, and logistically difficult. To approach this question more directly and more efficiently, one can utilize methods of PCR-based mutation detection for the characterization of progeny of mutagenized mice. Since this analysis can be done after a single generation of breeding, it is useful as a rapid means for the assessment of the efficiency of mutagen treatment. Furthermore, it is readily imaginable that this strategy can be applied for the general determination of gene function in a systematic manner. Theoretical considerations and empirical analysis suggest that the per-base mutation frequency for a fractionated-dose treatment protocol is on the order of 1 sequence change per 10(5) bp.

Animals↗
PubMed2000

Developmentally regulated expression of organic ion transporters NKT (OAT1), OCT1, NLT (OAT2), and Roct.

Several xenobiotic (organic cation and anion) transporters have recently been identified, although their endogenous substrates, if such exist, remain unknown. When we initially identified NKT, also known as OAT1, the first member of the organic anion transporter (OAT) family (Lopez-Nieto CE, You G, Bush KT, Barros EJ, Beier DR, and Nigam SK. J Biol Chem 272: 6471-6478, 1997), we noted its expression in the embryonic kidney. We have now demonstrated its transporter function and more fully examined the spatiotemporal expression patterns of representative organic ion transporters, [NKT (OAT1), Roct, OCT1, and NLT, also known as OAT2] during murine development. In the kidney, NKT (OAT1), OCT1, and Roct transcripts appeared at midgestation, coinciding with proximal tubule differentiation, and gradually increased during nephron maturation. A similar pattern was observed for NLT (OAT2) in the liver and kidney, although, in the kidney, NLT (OAT2) transcription did not increase as dramatically. The roughly cotemporal expression of these related transporters in the developing proximal tubule may indicate common transcriptional regulation. Expression during embryogenesis in extrarenal sites could suggest a role in the formation and maintenance of nonrenal tissues. Importantly, all four genes were expressed in unexpected places during nonrenal organogenesis: Roct in the fetal liver (temporally coinciding with the onset of hematopoiesis) and neural tissue; NKT (OAT1) in the fetal brain; OCT1 in the ascending aorta and atrium; and NLT (OAT2) in the fetal lung, intestine, skin, and developing bone. Because these gene products mediate the transport of a broad range of metabolites and toxins, it seems likely that, apart from their known functions, these transporters play a role in transport of organic molecules, perhaps including those with morphogenetic activity. These genes could also play important developmental roles independent of transport function.

Aging↗
PubMed2000

Genetic localization of interacting modifiers affecting severity in a murine model of polycystic kidney disease.

Genetic analysis of mouse disease models provides a means to investigate how modifying loci cause variation in phenotypic expression. We have shown that polycystic kidney disease (PKD) progression in the juvenile cystic kidney (jck) mutation can be influenced by an epistatic interaction between alleles of different strain backgrounds and we localized one of these loci to chromosome 1. Using a chromosome 1 congenic strain, we improved the genetic analysis and mapped the interacting locus to proximal chromosome 4, with a highly significant lod association of 5.5. Re-analysis of the original F(2) cross reveals that in this cohort, while the lod association of the chromosome 4 locus alone is not significant, its effect is apparent when analyzed in combination with the chromosome 1 locus. This result suggests that correlation of paired genotype data with phenotype data will be an effective means to detect epistatic interactions contributing to complex traits, and that these associations can be tested using appropriate congenic lines.

Alleles↗
PubMed1999

Cloning, tissue-specific expression, gene structure and chromosomal localization of human phosphatidylcholine transfer protein.

Phosphatidylcholine transfer protein (PC-TP) is a cytosolic protein that catalyzes intermembrane transfer of phosphatidylcholines in vitro. We have cloned a cDNA encoding the human ortholog of PC-TP and have determined its tissue-specific expression as well as genomic organization. Radiation hybrid mapping localized the human gene, PCTP, to chromosome 17q21-22 and PCR-based single strand conformation polymorphism analysis of an interspecific backcross assigned mouse Pctp to the region of syntenic conservation on chromosome 11.

Amino Acid Sequence↗
PubMed1999

Genetic analysis of modifying loci on mouse chromosome 1 that affect disease severity in a model of recessive PKD.

Using a cross between C57BL/6J and FVB/N mice, we have confirmed the localization on chromosome 1 of a modifying locus that affects the severity of polycystic kidney disease (PKD) in the juvenile cystic kidney (jck) mouse. Despite the highly significant contribution of this locus in F2 progeny of a cross between C57BL/6J and DBA/2J mice (4), a series of congenic strains carrying regions of chromosome 1 on a DBA/2J background did not show a severe disease phenotype. One possible explanation for these results is that this phenotype is caused by two linked loci, which have been separated in the congenic lines that were generated. This hypothesis is supported by the demonstration that severe PKD occurs in mice carrying a large congenic interval.

Animals↗
PubMed1999

Mucosal T lymphocyte numbers are selectively reduced in integrin alpha E (CD103)-deficient mice.

The mucosal lymphocyte integrin alpha E(CD103)beta 7 is thought to be important for intraepithelial lymphocyte (IEL) localization or function. We cloned the murine integrin gene encoding alpha E, localized it to chromosome 11, and generated integrin alpha E-deficient mice. In alpha E-/- mice, intestinal and vaginal IEL numbers were reduced, consistent with the known binding of alpha E beta 7 to E-cadherin expressed on epithelial cells. However, it was surprising that lamina propria T lymphocyte numbers were diminished, as E-cadherin is not expressed in the lamina propria. In contrast, peribronchial, intrapulmonary, Peyer's patch, and splenic T lymphocyte numbers were not reduced in alpha E-deficient mice. Thus, alpha E beta 7 was important for generating or maintaining the gut and vaginal T lymphocytes located diffusely within the epithelium or lamina propria but not for generating the gut-associated organized lymphoid tissues. Finally, the impact of alpha E deficiency upon intestinal IEL numbers was greater at 3-4 wk of life than in younger animals, and affected the TCR alpha beta+ CD8+ T cells more than the gamma delta T cells or the TCR alpha beta+ CD4+CD8- population. These findings suggest that alpha E beta 7 is involved in the expansion/recruitment of TCR alpha beta+ CD8+ IEL following microbial colonization. Integrin alpha E-deficient mice will provide an important tool for studying the role of alpha E beta 7 and of alpha E beta 7-expressing mucosal T lymphocytes in vivo.

Animals↗
PubMed1999

A novel putative transporter maps to the osteosclerosis (oc) mutation and is not expressed in the oc mutant mouse.

The phenotype of mice homozygous for the osteosclerosis (oc) mutation includes osteopetrosis, and a variety of studies demonstrate that osteoclasts in these mice are present but nonfunctional. We have identified a novel gene that has homology to a family of 12-transmembrane domain proteins with transport functions and maps to proximal mouse chromosome 19, in a region to which the oc mutation has been previously assigned. The putative transporter is abundant in normal kidney, but its expression is markedly reduced in kidneys from oc/oc mice when tested using Northern and Western analyses. Southern analysis of this gene, which we call Roct (reduced in oc transporter), demonstrates that it is intact and unrearranged in oc/oc mice. In situ studies show that Roct is expressed in developing bone. We propose that the absence of Roct expression results in an osteopetrosis phenotype in mice.

Amino Acid Sequence↗
PubMed1999

Cloning and functional expression of a mouse liver organic cation transporter.

Hepatic uptake of organic cations is essential for the metabolism and secretion of numerous endobiotics and drugs. Several hepatic organic cation transporters have been kinetically defined, yet have not been isolated or cloned. We have isolated a complementary DNA (cDNA) from both murine liver and kidney cDNA libraries (mOct1/Slc22a1), and have functionally expressed it in Xenopus laevis oocytes. Although mOct1/Slc22a1 is homologous to previously cloned rat and human organic cation transporters, organic cation transport kinetics differed markedly. mOct1/Slc22a1-RNA injection of oocytes resulted in the saturable, time- and temperature-dependent uptake of the quaternary organic cation [14C]-tetraethylammonium ([14C]-TEA), with a Km of 38 micromol/L. TEA uptake was inhibited by several other organic cation drugs, but was not inhibited by the organic cation n-methyl-nicotinamide (NMN), being instead stimulated by it (fourfold). [14C]-TEA uptake was also stimulated by an inside-outside proton gradient. mOct1/Slc22a1-injected oocytes transported the organic cations [3H]-1-methyl-4-phenylpyridium and [3H]-choline chloride, but did not transport other classes of organic compounds. mOct1/Slc22a1 encodes for a hepatic and renal organic cation transporter which may be important for the uptake and secretion of cationic drugs and endobiotics.

1-Methyl-4-phenylpyridinium↗
PubMed1999

Cloning and expression of a murine histone deacetylase 3 (mHdac3) cDNA and mapping to a region of conserved synteny between murine chromosome 18 and human chromosome 5.

Histone deacetylases (HDACs) are enzymes that play a pivotal role in transcription, differentiation, and cell cycle progression. We previously cloned human HDAC3 cDNA and showed that its transfection into THP-1 cells results in G2/M cell cycle accumulation. Using bioinformatic screening and PCR, we have now cloned the murine Hdac3 cDNA, which encodes a 428-amino-acid protein with near complete identity to its human ortholog. To establish a link to a potential disease locus, we performed PCR-based chromosomal mapping for the mHdac3 gene and chromosomal fluorescence in situ hybridization (FISH) for the human gene. mHdac3 localizes to chromosome 18 and human HDAC3 gene localizes to a syntenic region in chromosome 5 at band q31.3-q32 telomeric to the cytokine gene cluster. Transfection of mHdac3 into HeLa cells led to accumulation in G2/M. Our results suggest a cell cycle function for murine Hdac3, reflecting the complex regulatory roles of this gene family.

Amino Acid Sequence↗
PubMed1999

Quantitative trait locus mapping of airway responsiveness to chromosomes 6 and 7 in inbred mice.

Quantitative trait locus (QTL) mapping was used to identify chromosomal regions contributing to airway hyperresponsiveness in mice. Airway responsiveness to methacholine was measured in A/J and C3H/HeJ parental strains as well as in progeny derived from crosses between these strains. QTL mapping of backcross [(A/J x C3H/HeJ) x C3H/HeJ] progeny (n = 137-227 informative mice for markers tested) revealed two significant linkages to loci on chromosomes 6 and 7. The QTL on chromosome 6 confirms the previous report by others of a linkage in this region in the same genetic backgrounds; the second QTL, on chromosome 7, represents a novel locus. In addition, we obtained suggestive evidence for linkage (logarithm of odds ratio = 1.7) on chromosome 17, which lies in the same region previously identified in a cross between A/J and C57BL/6J mice. Airway responsiveness in a cross between A/J and C3H/HeJ mice is under the control of at least two major genetic loci, with evidence for a third locus that has been previously implicated in an A/J and C57BL/6J cross; this indicates that multiple genetic factors control the expression of this phenotype.

Animals↗
PubMed1999

Isoforms of the Na-K-2Cl cotransporter in murine TAL I. Molecular characterization and intrarenal localization.

We have identified several alternatively spliced cDNAs encoding mBSC1, an apical bumetanide-sensitive Na+-K+-2Cl- cotransporter from mouse kidney. Two full-length clones were isolated, designated C4 and C9, predicting proteins of 770 and 1,095 amino acids, respectively. The C4 isoforms are generated by utilization of an alternative polyadenylation site located within the intron between exons 16 and 17 of the mBSC1 gene on chromosome 2; the resultant transcripts predict a truncated COOH terminus ending in a unique 55 amino acid sequence. The predicted C4 and C9 COOH termini differ in the distribution of putative phosphorylation sites for both protein kinase A and C. Independent splicing events involve three previously described cassette exons, which are predicted to encode most of the second transmembrane domain. A total of six different isoforms are expressed, generated by the combinatorial association of three cassette exons and two alternative 3' ends. C9-specific and C4-specific antibodies detect proteins of approximately 150 and 120 kDa, respectively, in mouse kidney. Immunofluorescence and immunohistochemistry indicate expression of both COOH-terminal isoforms within the thick ascending limb of the loop of Henle (TAL). However, staining with the C4 antibody is more heterogeneous, with a decreased proportion of positive cells in the cortical TAL. Functional expression in Xenopus oocytes indicates a dominant negative function for C4 isoforms [companion study, C. Plata, D. B. Mount, V. Rubio, S. C. Hebert, and G. Gamba. Am. J. Physiol. 276 (Renal Physiol. 45): F347-F358, 1999], and the differential expression of these isoforms may contribute to functional heterogeneity of Na+-K+-2Cl- cotransport in mouse TAL.

Amino Acid Sequence↗