PEX12, the Pathogenic Gene of Group III Zellweger Syndrome: cDNA Cloning by Functional Complementation on a CHO Cell Mutant, Patient Analysis, and Characterization of Pex12p

Rat PEX12 cDNA was isolated by functional complementation of peroxisome deficiency of a mutant CHO cell line, ZP109 (K. Okumoto, A. Bogaki, K. Tateishi, T. Tsukamoto, T. Osumi, N. Shimozawa, Y. Suzuki, T. Orii, and Y. Fujiki, Exp. Cell Res. 233:11–20, 1997), using a transient transfection assay and an ectopic, readily visible marker, green fluorescent protein. This cDNA encodes a 359-amino-acid membrane protein of peroxisomes with two transmembrane segments and a cysteine-rich zinc finger, the RING motif. A stable transformant of ZP109 with the PEX12 was morphologically and biochemically restored for peroxisome biogenesis. Pex12p was shown by expression of bona fide as well as epitope-tagged Pex12p to expose both N- and C-terminal regions to the cytosol. Fibroblasts derived from patients with the peroxisome deficiency Zellweger syndrome of complementation group III (CG-III) were also complemented for peroxisome biogenesis with PEX12. Two unrelated patients of this group manifesting peroxisome deficiency disorders possessed homozygous, inactivating PEX12 mutations: in one, Arg180Thr by one point mutation, and in the other, deletion of two nucleotides in codons for ²⁹¹Asn and ²⁹²Ser, creating an apparently unchanged codon for Asn and a codon 292 for termination. These results indicate that the gene encoding peroxisome assembly factor Pex12p is a pathogenic gene of CG-III peroxisome deficiency. Moreover, truncation and site mutation studies, including patient PEX12 analysis, demonstrated that the cytoplasmically oriented N- and C-terminal parts of Pex12p are essential for biological function.     

Release of salmon gonadotropin and 17α-hydroxyprogesterone from lipophilized gelatin emulsion at 10, 20 and 30°C in the Japanese eel

Hormone releasing properties from an emulsion prepared with lipophilized gelatin (LG emulsion) were investigated on salmon gonadotropin (sGTH) as a peptide hormone and 17-hydroxyprogesterone (17P) as a steroid at 10, 20 and 30°C by monitoring plasma profiles of these hormones after administration in the Japanese eel. Release of these hormones from the LG emulsion were slow and not largely influenced by water temperature, whereas release from saline solution (sGTH) or cottonseed oil (17P) were rapid and increased with the elevation of temperature. © Rapid Science Ltd. 1998     

Complete nucleotide sequence of pSTK1, a cryptic plasmid from Bacillus stearothermophilus TK015

Summary The complete nucleotide sequence of pSTK1, a cryptic plasmid isolated from B. stearothermophilus TK015, has been determined. pSTK1 has been shown to be 1883 bp in length and contain three open reading frames (ORFs), one of which has a helix-turn-helix motif typical of DNA-binding proteins. Also identified was a region that can form an extensive secondary structure, which would show a high degree of similarity to palA, an origin for minus strand elongation in rolling circle replication.     

Variation in gene expression and aberrantly regulated chromosome regions in cloned mice

DNA microarray analysis was used to determine the precise genome-wide gene expression profiles of somatic cloned mice derived from Sertoli and cumulus cells. It demonstrated unexpectedly large epigenetic diversity in neonatal cloned mice, despite their normal appearance and genetic identity. In three neonatal tissues of the cloned mice, the expression of 9-40% of the genes examined was more than two times higher or lower in donor cell-dependent or -independent manners compared with normal controls. Relatively few (0.4-4%) of the genes exhibited up- or downregulation in the same manner in both types of clone. A cluster analysis of the variation in gene expression led to the identification of several chromosome regions in which gene expression was aberrantly controlled in the somatic clones. These results provide a more complete understanding of how somatic clones differ from each other and from normal individuals produced by sexual reproduction and indicate the significant difficulties that face the application of somatic cloning in regenerative medicine.     

Mutation in recR gene of Deinococcus radiodurans and possible involvement of its product in the repair of DNA interstrand cross-links

We previously reported that some Deinococcus radiodurans mutants are sensitive to DNA interstrand cross-linking agents but resistant to UV and gamma-rays. We isolated DNA fragments from a D. radiodurans genomic library which complemented the mitomycin C sensitivity of one of these mutants. One 3.2kb-long fragment contains an open reading frame of approximately 700bp and the deduced amino acid sequence is very homologous to other prokaryotic RecR proteins. This open reading frame in the mitomycin C-sensitive mutant strain contains a frame shift mutation at its carboxyl terminal region. These data suggest that RecR protein plays an important role in the resistance to interstrand cross-links in this bacterium.     

Dynamic cerebral autoregulation during exhaustive exercise in humans

We investigated whether dynamic cerebral autoregulation is affected by exhaustive exercise using transfer-function gain and phase shift between oscillations in mean arterial pressure (MAP) and middle cerebral artery (MCA) mean blood flow velocity (V(mean)). Seven subjects were instrumented with a brachial artery catheter for measurement of MAP and determination of arterial Pco(2) (Pa(CO(2))) while jugular venous oxygen saturation (Sv(O(2))) was determined to assess changes in whole brain blood flow. After a 10-min resting period, the subjects performed dynamic leg-cycle ergometry at 168 +/- 5 W (mean +/- SE) that was continued to exhaustion with a group average time of 26.8 +/- 5.8 min. Despite no significant change in MAP during exercise, MCA V(mean) decreased from 70.2 +/- 3.6 to 57.4 +/- 5.4 cm/s, Sv(O(2)) decreased from 68 +/- 1 to 58 +/- 2% at exhaustion, and both correlated to Pa(CO(2)) (5.5 +/- 0.2 to 3.9 +/- 0.2 kPa; r = 0.47; P = 0.04 and r = 0.74; P < 0.001, respectively). An effect on brain metabolism was indicated by a decrease in the cerebral metabolic ratio of O(2) to [glucose + one-half lactate] from 5.6 to 3.8 (P < 0.05). At the same time, the normalized low-frequency gain between MAP and MCA V(mean) was increased (P < 0.05), whereas the phase shift tended to decrease. These findings suggest that dynamic cerebral autoregulation was impaired by exhaustive exercise despite a hyperventilation-induced reduction in Pa(CO(2)).     

Molecular phylogenetic relationships among seven Japanese species of Cercopithifilaria

DNA sequences from a portion of the mitochondrial COI gene were used to clarify phylogenetic relationships among Japanese species in the genus Cercopithifilaria. Sequences were determined from seven Japanese species, five (C. shohoi, C. multicauda, C. minuta, C. tumidicervicata and C. bulboidea) from the serow (Capricornis crispus F. Bovidae) and two (C. longa and C. crassa) from the sika deer (Cervus nippon nippon F. Cervidae). No base substitutions were observed between C. bulboidea and C. longa, suggesting that recent host switching of a lineage of C. bulboidea between bovid and cervid hosts gave rise to C. longa. In phylogenetic trees inferred using a variety of methods, the morphologically ancestral type, C. bulboidea, appeared as a derived species. C. multicauda was found to be basal in the analyses. It seems therefore that C. multicauda is the most primitive out of the seven species.     

De novo formation of basal bodies in Naegleria gruberi: regulation by phosphorylation

The de novo formation of basal bodies in Naegleria gruberi was preceded by the transient formation of a microtubule (MT)-nucleating complex containing gamma-tubulin, pericentrin, and myosin II complex (GPM complex). The MT-nucleating activity of GPM complexes was maximal just before the formation of visible basal bodies and then rapidly decreased. The regulation of MT-nucleating activity of GPM complexes was accomplished by a transient phosphorylation of the complex. Inhibition of dephosphorylation after the formation of basal bodies resulted in the formation of multiple flagella. 2D-gel electrophoresis and Western blotting showed a parallel relationship between the MT-nucleating activity of GPM complexes and the presence of hyperphosphorylated gamma-tubulin in the complexes. These data suggest that the nucleation of MTs by GPM complexes precedes the de novo formation of basal bodies and that the regulation of MT-nucleating activity of GPM complexes is essential to the regulation of basal body number.