Duplication of the short arm of the X chromosome in mother and daugther

An 11-year-old girl with short stature, mental retardation, and mild dysmorphic features was found to have an inverted duplication of most of the short arm of the X chromosome [dic inv dup(X)(qterp22.3: :p22.3 cen:)]. Her mother, who is also short and retarded, carries the same duplication. Fluorescence in situ hybridization with an X chromosome library, and with X centromerespecific alpha satellite and telomere probes, was useful in characterizing the duplication. In most females with structurally abnormal X chromosomes, the abnormal chromosome is inactivated. Although the duplicated X was consistently late replicating in the mother, X chromosome inactivation studies in the proband indicated that in 11% of her lymphocytes the duplicated X was active.     

Postural hypotension and diuretic therapy in the elderly.

Blood pressures were recorded in 319 ambulatory subjects, largely men, age 50 to 99 years. The mean systolic pressures were maximal in the seventh and eighth decades (136.0 and 132.1 mm Hg with the subjects supine and erect, respectively), whereas the mean diastolic pressures fell progressively after age 69. The distribution of postural changes in mean blood pressure was similar in each decade; a decrease of 20 mm Hg on more was noted in 3.4% of the subjects aged 80 to 99 years and in 4.1% of those aged 50 to 79 years. The frequency of postural hypotension was 4.6% in subjects treated with diuretics and 3.4% in those not so treated. Blood pressures and the frequency of postural hypotension did not progressively increase in age in this elderly population.     

Tissue-specific expression of the alternative oxidase in soybean and siratro

Alternative oxidase activity (cyanide-insensitive respiration) was measured in mitochondria from the shoots, roots, and nodules of soybean (Glycine max L.) and siratro (Macroptilium atropurpureum) plants. Activity was highest in the shoots and lowest in the nodules. Alternative oxidase activity was associated with one (roots) or two (shoots) proteins between 30 and 35 kilodaltons that were detected by western blotting with a monoclonal antibody against Sauromatum guttatum alternative oxidase. No such protein was detected in nodule mitochondria. Measurements of oxygen uptake by isolated soybean root and nodule cells in the presence of cyanide and salicylhydroxamic acid indicated that alternative oxidase activity was confined to the uninfected cortex cells of the nodule. Immunoprecipitation of translation products of mRNA isolated from soybean shoots revealed a major band at 43 kilodaltons that is assumed to be the precursor of an alternative oxidase protein. This band was not seen when mRNA from nodules was treated in the same fashion. The results indicate that tissue-specific expression of the alternative oxidase occurs in soybean and siratro.     

Binding of ethidium derivatives to natural DNA: a 300 MHz 1H NMR study.

The binding of three ethidium derivatives, ethidium (1), des-3-amino ethidium (2) and des-8-amino ethidium (3), to short (approximately 35 base pairs), random sequence DNA has been investigated using 300 MHz proton NMR. At 35 degrees C all three drugs cause upfield shifts of the resonances from the exchangeable imino protons, as expected for intercalative binding to DNA. However, the lineshapes vary significantly with the nature of the drug. The temperature dependence of the spectra of the DNA shows that differences between spectra observed at 35 degrees C with ethidium and with des-3-amino ethidium are primarily due to differences in the drug binding kinetics rather than to differences in mode of binding. Removal of the amino group at position 3, but not at position 8, on the parent ethidium shortens the lifetime of the intercalative state; this implies that the 3-NH2 group is involved in stabilization of the drug-DNA complex. Analysis of the drug-DNA spectra indicates that there is a preference for binding of the drugs adjacent to G.C base pairs.     

BMP-2 induces the expression of activin betaA and follistatin in vitro

Activins are members of the transforming growth factor beta (TGF-beta) superfamily and have been shown to be multifunctional regulators of development and cell differentiation. Increasing evidence suggests activin betaA is involved in skeletal development. Using differential display PCR we have identified activin betaA as a gene associated with recombinant human bone morphogenetic protein-2 (rhBMP-2) induced differentiation of a mouse limb bud cell line, MLB13MYC clone 17, from a prechondroblastic to an osteoblastic phenotype. The expression of activin betaA peaks at 24 h of rhBMP-2 treatment, before detection of osteocalcin mRNA expression. Cycloheximide treatment inhibits induction of activin betaA, indicating a requirement for new protein synthesis. The induction of the mRNA encoding follistatin, an activin binding protein, was also examined. Follistatin mRNA increases within 18 h of rhBMP-2 treatment, as activin betaA mRNA increases but before it peaks. Treatment of MLB13MYC clone 17 cells with purified activin betaA concomitant with rhBMP-2 does not affect markers of chondrocyte or osteoblast differentiation, nor does treatment with purified activin betaA alone. This suggests that activin betaA exerts its effect via a paracrine mechanism. In situ hybridization analysis demonstrates that activin betaA expression is localized to cells in the developing interphalangeal joints of embryonic mouse limbs. This is consistent with in vivo induction by BMP-2 which is also expressed in the developing joints. Activin betaA, therefore, is downstream from BMP-2 in the cascade of events that result in skeletal development.     

Identification of a novel family of nonclassic yeast phosphatidylinositol transfer proteins whose function modulates phospholipase D activity and Sec14p-independent cell growth

Yeast phosphatidylinositol transfer protein (Sec14p) is essential for Golgi function and cell viability. We now report a characterization of five yeast SFH (Sec Fourteen Homologue) proteins that share 24-65% primary sequence identity with Sec14p. We show that Sfh1p, which shares 64% primary sequence identity with Sec14p, is nonfunctional as a Sec14p in vivo or in vitro. Yet, SFH proteins sharing low primary sequence similarity with Sec14p (i.e., Sfh2p, Sfh3p, Sfh4p, and Sfh5p) represent novel phosphatidylinositol transfer proteins (PITPs) that exhibit phosphatidylinositol- but not phosphatidylcholine-transfer activity in vitro. Moreover, increased expression of Sfh2p, Sfh4p, or Sfh5p rescues sec14-associated growth and secretory defects in a phospholipase D (PLD)-sensitive manner. Several independent lines of evidence further demonstrate that SFH PITPs are collectively required for efficient activation of PLD in vegetative cells. These include a collective requirement for SFH proteins in Sec14p-independent cell growth and in optimal activation of PLD in Sec14p-deficient cells. Consistent with these findings, Sfh2p colocalizes with PLD in endosomal compartments. The data indicate that SFH gene products cooperate with "bypass-Sec14p" mutations and PLD in a complex interaction through which yeast can adapt to loss of the essential function of Sec14p. These findings expand the physiological repertoire of PITP function in yeast and provide the first in vivo demonstration of a role for specific PITPs in stimulating activation of PLD.     

Genome screening in human systemic lupus erythematosus: results from a second Minnesota cohort and combined analyses of 187 sib-pair families

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by a loss of immunologic tolerance to a multitude of self-antigens. Epidemiological data suggest an important role for genes in the etiology of lupus, and previous genetic studies have implicated the HLA locus, complement genes, and low-affinity IgG (Fcgamma) receptors in SLE pathogenesis. In an effort to identify new susceptibility loci for SLE, we recently reported the results of a genomewide microsatellite marker screen in 105 SLE sib-pair families. By using nonparametric methods, evidence for linkage was found in four intervals: 6p11-21 (near the HLA), 16q13, 14q21-23, and 20p12.3 (LOD scores >/=2.0), and weaker evidence in another nine regions. We now report the results of a second complete genome screen in a new cohort of 82 SLE sib-pair families. In the cohort 2 screen, the four best intervals were 7p22 (LOD score 2.87), 7q21 (LOD score 2.40), 10p13 (LOD score 2.24), and 7q36 (LOD score 2.15). Eight additional intervals were identified with LOD scores in the range 1.00-1.67. A combined analysis of MN cohorts 1 and 2 (187 sib-pair families) showed that markers in 6p11-p21 (D6S426, LOD score 4.19) and 16q13 (D16S415, LOD score 3.85) met the criteria for significant linkage. Three intervals (2p15, 7q36, and 1q42) had LOD scores in the range 1.92-2.06, and another 13 intervals had LOD scores in the range of 1.00-1.78 in the combined sample. These data, together with other available gene mapping results in SLE, are beginning to allow a prioritization of genomic intervals for gene discovery efforts in human SLE.