A long Y chromosome in man

Summary An unusually long Y chromosome was described in the phenotypically normal father and paternal grandfather of a girl with Down's syndrome, and likewise in a male infant with multiple malformations and his father, normal in phenotype. Measurements revealed that the long Y chromosome corresponded in length to autosomes of group 16–18.Information was obtained to show that the increased length of the Y chromosome was an inheritable character, and that a long Y chromosome was not always associated with an abnormal phenotype (or phenotypes).Contribution No. 585 from the Zoological Institute, Hokkaido University.     

TMBP200, a XMAP215 homologue of tobacco BY-2 cells,has an essential role in plant mitosis

TMBP200 from tobacco BY-2 cells is a member of the highly conserved family of microtubule-associated proteins that includes Xenopus XMAP215, human TOGp, and Arabidopsis MOR1/GEM1. XMAP215 homologues have an essential role in spindle assembly and function in animals and yeast, but their role in plant mitosis is not fully clarified. Here, we show by immunoblot analysis that TMBP200 levels in synchronously cultured BY-2 cells increased when the cells entered mitosis, thus indicating that TMBP200 plays an important role in mitosis in tobacco. To investigate the role of TMBP200 in mitosis, we employed inducible RNA interference to silence TMBP200 expression in BY-2 cells. The resulting depletion of TMBP200 caused severe defects in bipolar spindle formation and resulted in the appearance of multinucleated cells with variable-sized nuclei. This finding indicates that TMBP200 has an essential role in bipolar spindle formation and function.     

Purification and characterization from bovine brain cytosol of two GTPase-activating proteins specific for smg p21, a GTP-binding protein having the same effector domain as c-ras p21s

The smg-21 GTP-binding protein (smg p21) has the same effector domain as the ras proteins (ras p21s) and is identical with the proteins of the rap1A and Krev-1 genes. In this paper, two proteins stimulating the GTPase activity of smg p21 are partially purified from bovine brain cytosol. These proteins, designated as smg p21 GTPase-activating protein (GAP) 1 and 2, are separated from a c-ras p21 GAP described previously by column chromatographies. smg p21 GAP1 and -2 stimulate the GTPase activity of only smg p21 but not that of c-Ha-ras p21 or the rho and smg-25A GTP-binding proteins. smg p21 GAP1 or -2 does not stimulate the dissociation of guanosine 5'-3-O-(thio)triphosphate or GDP from smg p21. smg p21 GAP1 or -2 themselves do not have GTP/GDP binding or GTPase activity. The Mr values of smg p21 GAP1 and -2 are estimated to be 250-400 x 10(3) and 80-100 x 10(3) by gel filtration and sucrose density gradient ultracentrifugation, respectively. The activity of smg p21 GAP1 and -2 is killed by tryptic digestion or heat boiling. These results indicate that bovine brain contains two smg p21 GAPs in addition to c-ras p21 GAP.     

Optimum culture conditions for the production of N-substituted formamide deformylase by Arthrobacter pascens F164

We investigated the optimum culture conditions for the production of a novel enzyme, N-substituted formamide deformylase, which acts mainly on N-benzylformamide, in Arthrobacter pascens F164. The highest enzyme activity was obtained when this strain F164 was cultivated in a synthetic medium with N-benzylformamide as sole nitrogen source. This deformylase was found to be an inducible enzyme depending on N-benzylformamide.     

Electrostatically constrained alpha-helical peptide inhibits replication of HIV-1 resistant to enfuvirtide

Alpha-helical peptides, such as T-20 (enfuvirtide) and C34, derived from the gp41 carboxyl-terminal heptad repeat (C-HR) of HIV-1, inhibit membrane fusion of HIV-1 and the target cells. Although T-20 effectively suppresses the replication of multi-drug resistant HIV variants both in vitro and in vivo, prolonged therapy with T-20 induces emergence of T-20 resistant variants. In order to suppress the emergence of such resistant variants, we introduced charged and hydrophilic amino acids, glutamic acid (E) and lysine (K), at the solvent accessible site of C34. In particular, the modified peptide, SC34EK, demonstrates remarkably potent inhibition of membrane fusion by the resistant HIV-1 variants as well as wild-type viruses. The activity was specific to HIV-1 and little influenced by serum components. We found a strong correlation between the anti-HIV-1 activities of these peptides and the thermostabilities of the 6-helix bundles that are formed with these peptides. We also obtained the crystal structure of SC34EK in complex with a 36 amino acid sequence (N36) comprising the amino-terminal heptad repeat of HIV-1. The EK substitutions in the sequence of SC34EK were directed toward the solvent and generated an electrostatic potential, which may result in enhanced alpha-helicity of the peptide inhibitor. The 6-helix bundle complex of SC34EK with N36 appears to be structurally similar to that of C34 and N36. Our approach to enhancing alpha-helicity of the peptide inhibitor may enable future design of highly effective and specific HIV-1 inhibitors.     

Left and Right Lung Asynchrony as a Physiological Indicator for Unilateral Bronchial Obstruction in Interventional Bronchoscopy

Background

In patients with bronchial obstruction, pulmonary function tests may not change significantly after intervention. The airflow asynchrony in both lungs due to unilateral bronchial obstruction may be applicable as a physiological indicator. The airflow asynchrony is reflected by the difference in the left and right lung sound development at tidal breathing.

Objectives

To investigate the usefulness of left and right lung asynchrony due to unilateral bronchial obstruction as a physiological indicator for interventional bronchoscopy.

Methods

Fifty cases with central airway obstruction were classified into three groups: tracheal, bronchial and extensive obstruction. The gap index was defined as the absolute value of the average of gaps between the left and right lung sound intensity peaks for a 12-second duration.

Results

Before interventional bronchoscopy, the gap index was significantly higher in the bronchial (p<0.05) and extensive obstruction groups (p<0.05) than in the tracheal group. The gap index in cases with unilateral bronchial obstruction of at least 80% (0.18±0.04 seconds) was significantly higher than in cases with less than 80% obstruction (0.02±0.01 seconds, p<0.05). After intervention for bronchial obstruction, the dyspnea scale (p<0.001) and gap index significantly improved (p<0.05), although no significant improvements were found in spirometric assessments. The responder rates for dyspnea were 79.3% for gap indexes over 0.06 seconds and 55.6% for gap indexes of 0.06 seconds or under.

Conclusions

Assessment of left and right lung asynchrony in central airway obstruction with bronchial involvement may provide useful physiological information for interventional bronchoscopy.     

Genomic rearrangement at 10q24 in non-syndromic split-hand/split-foot malformation

Split-hand/split-foot malformation (SHFM) is a congenital limb malformation characterized by a median cleft of hand and/or foot due to the absence of central rays. Five loci for syndromic and non-syndromic SHFM, termed SHFM1-5, have been mapped to date. Recently, a 0.5 Mb tandem genomic duplication was found at chromosome 10q24 in SHFM3 families. To refine the minimum duplicated region and to further characterize the SHFM3 locus, we screened 28 non-syndromic SHFM families for tandem genomic duplication of 10q24 by Southern blot and sequence analysis of the dactylin gene. Of 28 families, only two showed genomic rearrangements. Representative patients from the two families exhibit typical SHFM, with symmetrically affected hands and feet. One patient is a familial case with a 511,661 bp tandem duplication, whereas the second is a sporadic case arising from a de novo, 447,338 bp duplication of maternal origin. The smaller duplication in the second patient contained the LBX1, BTRC, POLL, and DPCD genes and a disrupted extra copy of the dactylin gene, and was nearly identical to the smallest known duplicated region of SHFM3. Our results indicate that genomic rearrangement of SHFM3 is rare among non-syndromic SHFM patients and emphasize the importance of screening for genomic rearrangements even in sporadic cases of SHFM.     

Multi-gene gateway clone design for expression of multiple heterologous genes in living cells: conditional gene expression at near physiological levels

Using Multisite Gateway five-DNA-fragment constructs vectors that enable expression of two tandemly situated cDNAs on a single plasmid were developed. Heterologous protein production in cells was achieved by modulating respective cDNA expression to pre-determined and different levels. Optimization of cDNA expression at near physiological protein levels was achieved using promoters from four cell cycle-dependent genes. In comparison with conventionally available promoters, EF-1alpha or CMV, the promoters used in this study were able to modulate cDNA expression levels over a magnitude of approximately 10 or 100-fold, respectively. In transiently transfected cells, two different proteins (CPalpha1 and CPbeta2), which form a heterodimer, each labeled with a different-colored fluorescent protein, were successfully synthesized at pre-determined levels from their respective cDNAs. The above vectors were designed to contain an FRT/Flp recombination site for integration onto chromosomes and for establishment of stable clones in HeLa cells by site-specific recombination. In the stable transformant cells produced only about 4% of the protein production levels measured in the transiently transformed cells. The biological significance of these observations is discussed.