PubMed Health⌕ Search

Biomedical subjects

D F Callen

Publications and source records attributed to D F Callen.

At least 91 records · Page 5Linked to original sources

Physical and genetic mapping of the dipeptidase gene DPEP1 to 16q24.3.

We report the subregional physical and genetic mapping on chromosome 16q of a cDNA clone selected as a potential tumor/growth suppressor sequence. By DNA sequencing and RNA expression pattern, this clone was identified as part of the renal dipeptidase gene (DPEP1). Using somatic cell hybrids carrying either different human chromosomes or chromosome 16 segments, we confirm and refine the physical mapping of DPEP1 to the chromosome 16 subregion q24.3. Two RFLPs, a biallelic polymorphism detected by TaqI and a VNTR detected by BamHI, EcoRI, and BglII, are described. Using the VNTR polymorphism, DPEP1 was shown to be linked to D16S7 with a maximum lod score of 5.8 at a recombination fraction of 0.03.

Animals↗

Fine genetic mapping of the Batten disease locus (CLN3) by haplotype analysis and demonstration of allelic association with chromosome 16p microsatellite loci.

Batten disease, juvenile onset neuronal ceroid lipofuscinosis, is an autosomal recessive neurodegenerative disorder characterized by accumulation of autofluorescent lipopigment in neurons and other cell types. The disease locus (CLN3) has previously been assigned to chromosome 16p. The genetic localization of CLN3 has been refined by analyzing 70 families using a high-resolution map of 15 marker loci encompassing the CLN3 region on 16p. Crossovers in three maternal meioses allowed localization of CLN3 to the interval between D16S297 and D16S57. Within that interval alleles at three highly polymorphic dinucleotide repeat loci (D16S288, D16S298, D16S299) were found to be in strong linkage disequilibrium with CLN3. Analysis of haplotypes suggests that a majority of CLN3 chromosomes have arisen from a single founder mutation.

Alleles↗

Smooth muscle myosin heavy chain locus (MYH11) maps to 16p13.13-p13.12 and establishes a new region of conserved synteny between human 16p and mouse 16.

The human smooth muscle myosin heavy chain locus (MYH11) was mapped by fluorescence in situ hybridization to the middle of the p arm of chromosome 16 using a genomic cosmid clone containing coding sequences of the gene as probe. Probe from coding sequence, when applied to Southern blots of a panel of hybrids containing different portions of human chromosome 16, localized the gene to 16p13.13-13.12. Coding sequence PCR primers, when used on the DNA from a CHO-mouse hybrid clone mapping panel informative for mouse chromosomes, showed that the gene was located on mouse chromosome 16. These results correct a recent assignment of MYH11 from 16q12.2 to the region of the 16p-arm inversion breakpoint seen in acute myelomonocytic leukemia (AMML) M4Eo and demonstrate that the conflicting data do not result from the presence of additional MYH genes on the q arm of the chromosome. Also, a new region of conserved synteny between human 16p and mouse 16 is established.

Animals↗

Identification and regional localization of a human IMP dehydrogenase-like locus (IMPDHL1) at 16p13.13.

Sequence-tagged sites (STSs) are versatile chromosomal markers for a variety of genome mapping efforts. In this report, we describe a randomly generated STS (323F4) from human chromosome 16 genomic DNA that has 90.0% sequence identity to the type I human inosine-5'-monophosphate dehydrogenase (IMPDH1) gene and 72% identity to the type II human inosine-5'-monophosphate dehydrogenase (IMPDH2) gene. Additional sequencing by primer walking has provided a total of 1380 bp of the human chromosome 16 sequence. The IMPDH-like sequence 323F4 was regionally localized by PCR analysis of a panel of somatic cell hybrids containing different portions of human chromosome 16 to 16p13.3-13.12, between the breakpoints found in hybrids CY196/CY197 and CY198. This regional mapping assignment was further refined to subband 16p13.13 by high-resolution fluorescence in situ hybridization using cosmid 323F4 as a probe. We conclude that a third, previously undescribed IMPDH locus, termed IMPDHL1, exists at human chromosome 16p13.13.

Animals↗

High resolution mapping of interstitial long arm deletions of chromosome 16: relationship to phenotype.

The breakpoints of seven interstitial deletions of the long arm of chromosome 16 and two ring chromosomes of this chromosome were mapped by in situ hybridisation or by analysis of mouse/human somatic cell hybrids containing the deleted chromosome 16. Use of a high resolution cytogenetic based physical map of chromosome 16 enabled breakpoints to be assigned to an average resolution of at least 1.6 Mb. In general, interstitial deletions involving q12 or q22.1 have broadly similar phenotypes though there are differences in specific abnormalities. Deletions involving regions more distal, from 16q22.1 to 16q24.1, were associated with relatively mild dysmorphism. One region of the long arm, q24.2 to q24.3, was not involved in any deletion, either in this study or in any previous report. Presumably, monosomy for this region is lethal. In contrast, patients with deletions of 16q21 have a normal phenotype. These results are consistent with the proposed distribution of genes, frequent in telomeric Giesma light band regions but infrequent in G positive bands.

Abnormalities, Multiple↗

Chromosomal assignment of the uromodulin gene (UMOD) to 16p13.11.

We report the chromosomal assignment on chromosome arm 16p of a cDNA clone isolated through its expression in mature kidney and lack of expression in several Wilms tumors. DNA sequencing and analysis of the pattern of RNA expression in different tissues identified this clone as a uromodulin (Tamm-Horsfall glycoprotein, uromucoid; UMOD) sequence. By hybridizing this clone to somatic cell hybrids carrying different human chromosomes or segments of chromosome 16, the gene for UMOD was localized to 16p13.11.

Animals↗

Integration of the cytogenetic and genetic linkage maps of human chromosome 16 using 50 physical intervals and 50 polymorphic loci.

A comprehensive genetic linkage map constructed from 50 loci represented by 68 markers was anchored to 50 cytogenetically defined intervals on human chromosome 16. The linear order of the loci on the cytogenetic map was compatible with the independently derived linear order on the genetic map. The sex-averaged genetic length is 164.5 cM, with an average distance between loci of 3.3 cM. Sex-specific distances are 132.8 cM in males and 201.8 cM in females. This is the first detailed synthesis of genetic and cytogenetic maps for any human chromosome and is the first step in correlating the genetic and physical maps of this chromosome. The combined map, containing 15 loci with a minimum heterozygosity of 60% and 6 PCR-formatted microsatellite markers, will be useful for assignment and regional localization of disease genes to this chromosome.

Chromosome Mapping↗

Refined physical mapping of chromosome 16-specific low-abundance repetitive DNA sequences.

Repetitive DNA sequences have been implicated in the origin of several disease phenotypes, including fragile X syndrome, myotonic dystrophy, and spinal bulbar atrophy. In addition, a complex family of chromosome 16-specific low-abundance repetitive (CH16LAR) DNA sequences have been mapped by fluorescence in situ hybridization to regions of chromosome 16 that undergo breakage/rearrangement in acute nonlymphocytic leukemia (ANLL) cells. It has been hypothesized that these repetitive sequences are causally related to the chromosome rearrangements found in ANLL. Here, we further refine the mapping of CH16LAR sequences with respect to the ANLL inversion breakpoints, using a panel of somatic cell hybrids containing 51 different chromosome 16 breakpoints. These studies indicate that CH16LAR sequences at 16p13 are in close proximity to the ANLL short-arm breakpoint region. However, the region containing the highest density of CH16LAR sequences on the long arm appears to be distal to the region where the ANLL long-arm breakpoint has been mapped. These studies further show that CH16LAR sequences map in close proximity to FRA16D and FRA16A.

Animals↗

Identification of an inversion 16 coexisting with an isochromosome 22q by in situ hybridization in a case of childhood AML M4e.

Rearrangements involving chromosome 16, including inv(16) (p13q22), del(16)(q22), and t(16;16)(p13;q22), are frequent findings in acute myeloblastic leukemia (AML). Each of these rearrangements can occur as the sole karyotypic change or in association with additional chromosomal abnormalities, including in decreasing order of frequency: trisomy 22, trisomy 8, and deletion of the long arm of chromosome 7. We report a pediatric case of de novo AML, M4e subtype, with a unique combination of inv(16) (p13q22) and i(22q) occurring within the same leukemic clone. The inv(16) was detected by fluorescence in situ hybridization (FISH) analysis with two cosmid probes specific for sequences flanking the inv(16) breakpoint on the long arm of chromosome 16. Use of a chromosome-22-specific painting probe unequivocally identified a small metacentric chromosome as an i(22q). This case illustrates a variation in the association of trisomy 22 with inv(16) and suggests that duplication of the long arm of chromosome 22 may contain critical gene(s) involved in the multistep process of evolution of leukemia with 16q22 abnormalities.

Child, Preschool↗

The morquio A syndrome (mucopolysaccharidosis IVA) gene maps to 16q24.3.

The gene for N-acetylgalactosamine-6-sulfatase, the deficiency of which results in Morquio A syndrome (mucopolysaccharidosis type IVA), was assigned to chromosome 16 at band q24.3 by fluorescence in situ hybridization. Localization of this band was confirmed by PCR analysis of a somatic cell hybrid panel used for fine mapping of chromosome 16.

Animals↗

Incidence and origin of "null" alleles in the (AC)n microsatellite markers.

Twenty-three (AC)n repeat markers from chromosome 16 were typed in the parents of the 40 CEPH (Centre d'Etude du Polymorphisme Humain) families. Where parents were informative, the entire families were then typed. There were seven markers in which null alleles were demonstrated, as recognized by the apparent noninheritance, by a sib, of a parental allele. Four of these markers showed a null allele in a single sibship, while in the other three at least 30% of the CEPH sibships were shown to have a null allele segregating. One null allele was sequenced and shown to be the result of an 8-bp deletion occurring within the priming sequence for PCR amplification of the (AC)n repeats. In gene mapping or in application to diagnosis, the presence of a segregating null allele will not corrupt the linkage data but could result in loss of information. In isolated instances a segregating null allele may be interpreted as nonpaternity. The presence of a null allele may generate misleading data when individuals are haplotyped to determine the presence of linkage disequilibrium with a disease gene.

Alleles↗

Nonlinkage of 16q markers to familial predisposition to Wilms' tumor.

Wilms' tumor (WT), a childhood cancer of the kidney, occurs in both familial and sporadic forms. Chromosome 11 genes have been implicated in the etiology of WT, and mutations in a gene at chromosomal band 11p13, WT1, have been identified in a few WT cases. However, 11p13 has been excluded as the site of the predisposition mutation segregating in several large WT families, which implies the existence of a non-11p familial predisposition gene. Recently, loss of heterozygosity for 16q markers located between chromosomal bands 16q13 and 16q22 has been reported in approximately 20% of sporadic Wilms' tumors. To determine if this region of 16q harbors the non-11p familial WT gene, a genetic linkage study of five WT families was undertaken. Using multipoint analyses, we ruled out genetic linkage of familial WT predisposition to 16q.

Chromosome Banding↗

Molecular cytogenetic and clinical studies of 42 patients with marker chromosomes.

The molecular cytogenetic characterization and clinical details of 20 patients with marker chromosomes are presented. These 20 patients, together with another 22 patients previously published, represent a cohort in which the chromosomal origin of the marker chromosomes was successfully determined in all but one case. Examination of the pooled data suggests that the satellited markers derived from chromosomes 14, 15 (when metacentric or submetacentric), those whose origin is either 13 or 21, and those small ring autosomal markers derived from both alphoid and satellite II or III pericentric heterochromatin of chromosomes 1, 9, 15, and 16 are all associated with a low risk of phenotypic abnormality. The markers identified as i(18p), ring chromosomes derived from various autosomes, and satellited markers derived from chromosome 22 are associated with a high risk of phenotypic abnormality. The phenotype of patients with acrocentric markers derived from chromosome 15 was equivocal, perhaps as a result of imprinting. Additional data are required to confirm these trends. The mild mental retardation and abnormal face of a patient with a small ring chromosome derived from chromosome 4 are described. Identification of patients with small rings originating from particular chromosomes may allow the recognition of new syndromes.

Cells, Cultured↗