Mapping of the gene for the p60 subunit of the human chromatin assembly factor (CAF1A) to the Down syndrome region of chromosome 21

Exon trapping was used to clone portions of genes from the Down syndrome critical region (DSCR) of human chromosome 21. One trapped sequence showed complete homology with nucleotide sequence U20980 (GenBank), which corresponds to the gene for the p60 subunit of the human chromatin assembly factor-1 (CAF1A). We mapped this gene to human chromosome 21 by fluorescence in situ hybridization, by the use of somatic cell hybrids, and by hybridization to chromosome 21-specific YACs and cosmids. The CAF1A gene localizes to YACs 745H11 and 230E8 of the Chumakov et al. (1992, Nature 359: 380) YAC contig, within the DSCR on 21q22. This CAF1A, which belongs to the WD-motif family of genes and interacts with other polypeptide subunits to promote assembly of histones to replicating DNA, may contribute in a gene dosage-dependent manner to the phenotype of Down syndrome.     

Bacterial contig map of the 21q11 region associated with Alzheimer's disease and abnormal myelopoiesis in Down syndrome

We present a high-resolution bacterial contig map of 3.4 Mb of genomic DNA in human chromosome 21q11-q21, encompassing the region of elevated disomic homozygosity in Down Syndrome-associated abnormal myelopoiesis and leukemia, as well as the markers, which has shown a strong association with Alzheimer's Disease that has never been explained. The map contains 89 overlapping PACs, BACs, or cosmids in three contigs (850, 850, and 1500 kb) with two gaps (one of 140-210 kb and the second <5 kb). To date, eight transcribed sequences derived by cDNA selection, exon trapping, and/or global EST sequencing have been positioned onto the map, and the only two genes so far mapped to this cytogenetic region, STCH and RIP140 have been precisely localized. This work converts a further 10% of chromosome 21q into a high-resolution bacterial contig map, which will be the physical basis for the long-range sequencing of this region. The map will also enable positional derivation of new transcribed sequences, as well as new polymorphic probes, that will help in elucidation of the role the genes in this region may play in abnormal myelopoiesis and leukemia associated with trisomy 21 and Alzheimer's Disease.     

The gene encoding the catalytic subunit C alpha of cAMP-dependent protein kinase (locus PRKACA) localizes to human chromosome region 19p13.1

OBJECTIVE: The importance of portal hypertensive gastropathy, as a potentially bleeding lesion in cirrhotics with portal hypertension, has recently been appreciated. Histologically, dilation of the mucosal and submucosal vessels of the stomach is noted in this entity. The possibility of nitric oxide acting as a mediator for this mucosal vascular dilation has not been explored. METHODS: We determined, in a group of 10 male cirrhotic patients with esophageal varices and endoscopic changes consistent with severe portal hypertensive gastropathy (Group A), the gastric mucosal nitric oxide synthase activity. This was determined by measuring the rate of conversion of [3H]-arginine to [3H]-citrulline. Serum levels of nitrates and nitrites, the end products of nitric oxide, were also measured. The results were compared with those of a group of 10 male controls with no liver disease (Group B). RESULTS: Gastric mucosal constitutive and inducible nitric oxide synthase levels were significantly higher in group A (125.4 +/- 4.3 and 259.7 +/- 5.5 pmol/mg protein/minute, respectively) than in group B (88 +/- 8.6 and 130.8 +/- 6.6 pmol/mg protein/minute, respectively) ( p < 0.002 and < 0.0001, respectively). Serum nitrate/nitrite levels were 30.1 +/- 3.2 nmol/ml in group A and 15.5 +/- 0.09 nmol/ml in group B (p < 0.001). CONCLUSIONS: We conclude that the significantly increased gastric mucosal nitric oxide synthase activity, in patients with portal hypertensive gastropathy, suggests an important role for nitric oxide in the pathogenesis of this mucosal lesion.     

Localization of the gene encoding the alpha subunit of human interleukin-5 receptor (IL5RA) to chromosome region 3p24-3p26

The chromosomal location of the human gene for the alpha subunit of interleukin-5 receptor (IL5RA) has been determined. The human IL5RA gene was localized to the short arm of chromosome 3 by Southern blot analysis of DNA from a panel of mouse-human hybrid somatic cell lines. The IL5RA gene has been further localized to human chromosome region 3p24-3p26 by in situ hybridization of a molecularly cloned IL5RA cDNA fragment to metaphase chromosomes. The results suggest that the IL5RA locus is unlinked to other members of the hematopoietic receptor family. Assignment of the IL5RA gene to chromosome 3 at bands p26-p24 raises the possibility that it may be altered by certain nonrandom chromosomal abnormalities arising in human hematopoietic malignancies and solid tumors.     

The gene for death agonist BID maps to the region of human 22q11.2 duplicated in cat eye syndrome chromosomes and to mouse chromosome 6

Cat eye syndrome (CES) is associated with a duplication of a segment of human chromosome 22q11.2. Only one gene, ATP6E, has been previously mapped to this duplicated region. We now report the mapping of the human homologue of the apoptotic agonist Bid to human chromosome 22 near locus D22S57 in the CES region. Dosage analysis demonstrated that BID is located just distal to the CES region critical for the majority of malformations associated with the syndrome (CESCR), as previously defined by a single patient with an unusual supernumerary chromosome. However, BID remains a good candidate for involvement in CES-related mental impairment, and its overexpression may subtly add to the phenotype of CES patients. Our mapping of murine Bid confirms that the synteny of the CESCR and the 22q11 deletion syndrome critical region immediately telomeric on human chromosome 22 is not conserved in mice. Bid and adjacent gene Atp6e were found to map to mousechromosome 6, while the region homologous to the DGSCR is known to map to mouse chromosome 16.     

The gene encoding human intestinal trefoil factor (TFF3) is located on chromosome 21q22.3 clustered with other members of the trefoil peptide family

The giant hemoglobin, which occurs in free solution in the blood of earthworms, contains copper and zinc and exhibits superoxide dismutase activity as assessed by competition assays using cytochrome c or nitroblue tetrazolium. On a molar basis, the activity of this hemoglobin was approximately 10% that of the mammalian copper, zinc superoxide dismutase. The dodecamer, which contains the globin chains but lacks the linker subunits, had very little activity when compared to the complete native molecule. This suggests that the superoxide dismutase activity resides in one of the linker subunits. This is the first report of a superoxide dismutase bound to a respiratory pigment.     

The gene encoding LERK-7 (EPLG7, Epl7), a ligand for the Eph-related receptor tyrosine kinases, maps to human chromosome 5 at band q21 and to mouse chromosome 17

The human uterine glandular epithelium undergoes a sequence of well characterized changes during the menstrual cycle that presumably play an important role in preparation for blastocyst implantation. The aim of this study was to measure objectively glandular volume over the entire menstrual cycle and compare the results with eight different clinical superovulation or hormone replacement therapy (HRT) subject groups. Endometrial biopsies were taken from control normal menstrual cycle subjects (n = 96), and eight other smaller groups of women who had received different in-vitro fertilization (IVF) related treatments. The total area of glandular epithelium was objectively measured from routine histological slides using computerized image analysis. Control menstrual cycle results showed a significantly greater gland area in the early secretory stage of the cycle than at any time between the early proliferative through to the mid-late proliferative stages (P < 0.05). IVF patients receiving clomiphene citrate and human menopausal gonadotrophin had a significantly smaller glandular area than those in the control groups at equivalent stages of the menstrual cycle. The use of progesterone supplementation removed this significant difference. Patients on the ?Flare' regime had the highest gland area, although this was not significantly different from controls. Buserelin down-regulation gave a gland area that was closest to the normal cycle controls. The three HRT groups showed high variability in gland volume between patients. The results from this study demonstrate that superovulation can cause significant alterations in endometrial gland volume, but that these do not necessarily preclude implantation.     

The human skeletal muscle adenine nucleotide translocator gene maps to chromosome 4q35 in the region of the facioscapulohumeral muscular dystrophy locus

The large number of sequenced clones of HIV-1 and related viruses made it possible to indicate conserved elements with potential regulatory or structural functions. Such analysis was combined with directed mutagenesis in order to investigate the importance of elements that may influence the initiation of plus-strand DNA synthesis. The main site for plus-strand initiation is a polypurine tract near the 3' end of the viral RNA (the 3' PPT). An exact copy of this PPT is located in the middle of the genome (the internal PPT). Upstream from the internal PPT there is an inverted repeat. Mutants designed to upset the internal PPT (i.e., purine to pyrimidine changes), as well as mutants designed to abolish the potential stem-loop formation (changes around the internal PPT or in the upstream inverted repeat) both resulted in viruses with a reduced ability to replicate. Upsetting the stem-loop formation was, however, less harmful than changing the polypurine nature of the PPT. Changing a conserved T on the 3' side of the PPT to a C did not affect the phenotype.     

Mapping of the gene encoding the regulatory subunit RII alpha of cAMP-dependent protein kinase (locus PRKAR2A) to human chromosome region 3p21.3-p21.2

We isolated by the differential display technique a novel gene that was expressed abundantly in adipose and female-specific tissues. The cDNA contained an open reading frame of 2097 nucleotides encoding a 699-amino-acid peptide. The predicted protein showed homology to several known extracellular matrix (ECM) proteins such as proteoglycan, keratocan, and decorin. Moreover, the amino acid sequence contained several possible functional domains that would participate in protein-protein interactions, including an RGD sequence, a von Willebrand factor domain (VWFC), and a leucine-rich repeat. These findings suggest that this novel protein functions in cell-cell and/or cell-ECM recognition processes. Northern blot analysis revealed expression predominantly in adipose tissue as well as female-specific organs such as mammary gland, ovary, and uterus among 20 human adult tissues examined. We assigned the gene to chromosome 9q22.3 by means of fluorescence in situ hybridization.     

Assignment of the gene encoding the limbic system-associated membrane protein (LAMP) to mouse chromosome 16B5 and human chromosome 3q13.2-q21

Both insulin and muscle contraction stimulate glucose transport activity. However, contraction stimulation does not involve the insulin signalling intermediate phosphatidylinositol 3-kinase (PI 3-kinase). Protein kinase B (PKB) has recently been identified as a direct downstream target of PI 3-kinase in the insulin signalling pathway. We have examined here whether the two stimuli share PKB as a convergent step in separate signalling pathways. Insulin stimulates both glucose transport, GLUT4 cell-surface content and PKB activity (by 4-6-fold above basal) in a wortmannin-sensitive manner in in vitro incubated rat soleus muscles. By contrast, muscle contraction, which stimulates glucose transport and the cell surface content of GLUT4 by 3-fold above basal levels, had no effect on PKB activity. These data demonstrate that PKB is not a mediator of contraction-induced glucose transport and GLUT4 translocation.     

Chromosomal localization of the human gene encoding the 51-kDa subunit of mitochondrial complex I (NDUFV1) to 11q13

The 51-kDa flavoprotein subunit of mitochondrial NADH:ubiquinone oxidoreductase (Complex I) [NADH dehydrogenase (ubiquinone), flavoprotein 1 (51 kDa); EC 1.6.5.3] plays an important role in the formation of the NADH-binding site and is believed to be the principal site of entry for electrons donated by NADH into the respiratory chain. Human cDNA fragments of the 51-kDa protein were generated by polymerase chain reaction and used to localize the gene (NDUFV1) for this subunit to 11q13 by two separate techniques. This region of the human genome is strongly implicated in a number of different forms of cancer.     

Isolation of cDNA for a novel human protein KNP-I that is homologous to the E. coli SCRP-27A protein from the autoimmune polyglandular disease type I (APECED) region of chromosome 21q22.3

We have isolated cDNA clones for a novel human protein KNP-I from fetal brain and bone marrow cDNA libraries. Northern blot analysis indicated that the KNP-I gene is ubiquitously expressed in various human tissues. Significant homology of the KNP-I protein with Escherichia coli anti-sigma cross-reacting protein (SCRP-27A) (44% identity) and zebrafish (Brachydanio rerio) esl protein (49% identity) suggested that the KNP-I protein may be involved in a basic cellular function. Genomic sequencing revealed that the KNP-I gene consists of seven exons spanning 12 kb. Exon 5 was involved in alternative splicing. The KNP-I gene was mapped between D21S1460 and D21S25 on human chromosome 21q22.3, 26 kb distal to a Not 1 site of D21S1460. Thus, this novel KNP-I gene could be a candidate gene for autoimmune polyglandular disease type I (APECED) and other disorders mapped to this region.     

Mapping of the gene encoding the B56 beta subunit of protein phosphatase 2A (PPP2R5B) to a 0.5-Mb region of chromosome 11q13 and its exclusion as a candidate gene for multiple endocrine neoplasia type 1 (MEN1)

The multiple endocrine neoplasia type 1 (MEN1) locus has been previously localised to 11q13 by combined tumour deletion mapping and recombination studies, and a 0.5-Mb region, flanked by PYGM and D11S449, has been defined. In the course of constructing a conting, we have identified the location of the gene encoding the B56 beta subunit of protein phosphatase 2A (PP2A), which is involved in cell signal transduction pathways and thus represents a candidate gene for MEN1. We have searched for mutations in the PP2A-B56 beta coding region, together with the 5' and 3' untranslated regions in six MEN1 patients. DNA sequence abnormalities were not identified and thus the PP2A-B56 beta gene is excluded as the candidate gene for MEN1. However, our precise localisation of PP2A-B56 beta to this region of 11q13 may help in elucidating the basis for other disease genes mapping to this generich region.