Essential Bacillus subtilis genes

To estimate the minimal gene set required to sustain bacterial life in nutritious conditions, we carried out a systematic inactivation of Bacillus subtilis genes. Among approximately 4,100 genes of the organism, only 192 were shown to be indispensable by this or previous work. Another 79 genes were predicted to be essential. The vast majority of essential genes were categorized in relatively few domains of cell metabolism, with about half involved in information processing, one-fifth involved in the synthesis of cell envelope and the determination of cell shape and division, and one-tenth related to cell energetics. Only 4% of essential genes encode unknown functions. Most essential genes are present throughout a wide range of Bacteria, and almost 70% can also be found in Archaea and Eucarya. However, essential genes related to cell envelope, shape, division, and respiration tend to be lost from bacteria with small genomes. Unexpectedly, most genes involved in the Embden-Meyerhof-Parnas pathway are essential. Identification of unknown and unexpected essential genes opens research avenues to better understanding of processes that sustain bacterial life.

Long non-coding RNA UCA1 promotes breast tumor growth by suppression of p27 (Kip1)

Functional genomics studies have led to the discovery of a large amount of non-coding RNAs from the human genome; among them are long non-coding RNAs (lncRNAs). Emerging evidence indicates that lncRNAs could have a critical role in the regulation of cellular processes such as cell growth and apoptosis as well as cancer progression and metastasis. As master gene regulators, lncRNAs are capable of forming lncRNA–protein (ribonucleoprotein) complexes to regulate a large number of genes. For example, lincRNA-RoR suppresses p53 in response to DNA damage through interaction with heterogeneous nuclear ribonucleoprotein I (hnRNP I). The present study demonstrates that hnRNP I can also form a functional ribonucleoprotein complex with lncRNA urothelial carcinoma-associated 1 (UCA1) and increase the UCA1 stability. Of interest, the phosphorylated form of hnRNP I, predominantly in the cytoplasm, is responsible for the interaction with UCA1. Moreover, although hnRNP I enhances the translation of p27 (Kip1) through interaction with the 5′-untranslated region (5′-UTR) of p27 mRNAs, the interaction of UCA1 with hnRNP I suppresses the p27 protein level by competitive inhibition. In support of this finding, UCA1 has an oncogenic role in breast cancer both in vitro and in vivo. Finally, we show a negative correlation between p27 and UCA in the breast tumor cancer tissue microarray. Together, our results suggest an important role of UCA1 in breast cancer.

Antimicrobial activity of a 13 amino acid tryptophan-rich peptide derived from a putative porcine precursor protein of a novel family of antibacterial peptides

It has long been speculated that porcine cathelin is an N-terminal fragment of a longer precursor protein which possesses antimicrobial activity. In an attempt to find such a precursor, a cDNA clone was recently isolated and sequenced by screening a cDNA library from porcine bone marrow. In order to identify the functional activity of the putative protein encoded by an open reading frame, we have synthesized various lengths of peptides that correspond to the C-terminal region of the protein and examined them for their antimicrobial activities. We found that a 13 amino acid tryptophan-rich region with the sequence of VRRFPWWWPFLRR had strong antimicrobial activity with a wide spectrum. It showed potency against Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Staphylococcus epidermidis, Proteus mirabilis, and Streptococcus group D as well as Aspergillus fumigatus. The action of this peptide is bactericidal rather than bacteriostatic and this activity is completely inhibited by 2 mM MgCl2. Our results indicate that the previously identified putative precursor encoded by the isolated cDNA indeed possesses a potent antimicrobial activity and that this 13 amino acid synthetic peptide is considered to be a potentially effective drug against various infectious agents.

Regulation of alternative splicing of Bcl-x by BC200 contributes to breast cancer pathogenesis

BC200 is a long non-coding RNA (lncRNA) that has been implicated in the regulation of protein synthesis, yet whether dysregulation of BC200 contributes to the pathogenesis of human diseases remains elusive. In this study, we show that BC200 is upregulated in breast cancer; among breast tumor specimens there is a higher level of BC200 in estrogen receptor (ER) positive than in ER-negative tumors. Further experiments show that activation of estrogen signaling induces expression of BC200. To determine the significance of ER-regulated BC200 expression, we knockout (KO) BC200 by CRISPR/Cas9. BC200 KO suppresses tumor cell growth in vitro and in vivo by expression of the pro-apoptotic Bcl-xS isoform. Mechanistically, BC200 contains a 17-nucleotide sequence complementary to Bcl-x pre-mRNA, which may facilitate its binding to Bcl-x pre-mRNA and recruitment of heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1, a known splicing factor. Consequently, hnRNP A2/B1 interferes with association of Bcl-x pre-mRNA with the Bcl-xS-promoting factor Sam68, leading to a blockade of Bcl-xS expression. Together, these results suggest that BC200 plays an oncogenic role in breast cancer. Thus, BC200 may serve as a prognostic marker and possible target for attenuating deregulated cell proliferation in estrogen-dependent breast cancer.

The expression of the KAI1 gene, a tumor metastasis suppressor, is directly activated by p53

KAI1 is a tumor metastasis suppressor gene that is capable of inhibiting the metastatic process in animals. The expression of the KAI1 gene also is found to be down-regulated during the tumor progression of prostate, breast, lung, bladder, and pancreatic cancers in humans, and this down-regulation appears to be at or posttranscription level. We have found that the tumor suppressor gene p53 can directly activate the KAI1 gene by interacting with the 5' upstream region. The p53 responding region is located at approximately 860 bases upstream of the transcriptional initiation site, and it contains a typical tandem repeat of the p53 consensus-binding sequence. A gel-shift mobility analysis showed that this sequence indeed had the ability to bind to the purified p53 protein. Mutations of this sequence abolished the responsiveness to p53 and also the binding ability to the p53 protein. Furthermore, immunohistochemical analysis of 177 samples of human prostate tumors revealed that the expression of the KAI1 gene was correlated strongly to that of the p53 gene and that the loss of these two markers resulted in poor survivals of patients. Our data indicate a direct relationship between p53 and KAI1 genes and suggest that the loss of p53 function, which is commonly observed in many types of cancer, leads to the down-regulation of the KAI1 gene, which may result in the progression of metastasis.

Adenovirus-mediated gene transfer and expression of human beta-glucuronidase gene in the liver, spleen, and central nervous system in mucopolysaccharidosis type VII mice

Mucopolysaccharidosis type VII (Sly syndrome) is a lysosomal storage disease caused by inherited deficiency of the lysosomal enzyme beta-glucuronidase. A murine model of this disorder has been well characterized and used to study a number of forms of experimental therapies, including gene therapy. We produced recombinant adenovirus that expresses human beta-glucuronidase and administered this recombinant adenovirus to beta-glucuronidase-deficient mice intravenously. The beta-glucuronidase activities in liver and spleen were elevated to 40% and 20%, respectively, of the heterozygote enzymatic level at day 16. Expression persisted for at least 35 days. Pathological abnormalities of these tissues were also improved, and the elevated levels of urinary glycosaminoglycans were reduced in treated mice. However, the beta-glucuronidase activity in kidney and brain was not significantly increased. After administration of the recombinant adenovirus directly into the lateral ventricles of mutant mice, the beta-glucuronidase activity in crude brain homogenates increased to 30% of heterozygote activity. Histochemical demonstration of beta-glucuronidase activity in brain revealed that the enzymatic activity was mainly in ependymal cells and choroid. However, in some regions, the adenovirus-mediated gene expression was also evident in brain parenchyma associated with vessels and in the meninges. These results suggest that adenovirus-mediated gene delivery might improve the central nervous system pathology of mucopolysaccharidosis in addition to correcting visceral pathology.

Spontaneously immortalized adult mouse Schwann cells secrete autocrine and paracrine growth-promoting activities

We established spontaneously immortalized Schwann cell lines from long-term cultures of adult mouse dorsal root ganglia and peripheral nerves. One of the cell lines, designated IMS32, responded to mitogenic stimuli by platelet-derived growth factor (PDGF)-BB, acidic and basic fibroblast growth factors (aFGF, bFGF), and transforming growth factors (TGF)-beta 1 and -beta 2, as determined by bromodeoxyuridine (BrdU) incorporation and double immunofluorescence for S100 and BrdU. Furthermore, conditioned media (CM) obtained from IMS32 cells showed mitogenic activity for both IMS32 cells and long-term cultured Schwann cells. Western blot analysis revealed TGF-beta-like molecule in the CM, and the activity was absorbed with anti-TGF-beta neutralizing antibody. Reverse transcription followed by polymerase chain reaction (RT-PCR) of IMS32 RNA revealed that these cells expressed TGF-beta 1, -beta 2, and -beta 3 transcripts. When rat pheochromocytoma PC12 cells were incubated with the CM, they developed neurite growth. Coculture of PC12 and IMS32 cells also showed neurite growth of PC12 cells. RNA transcripts of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT3), ciliary neurotrophic factor (CNTF), and glial cell line-derived neurotrophic factor (GDNF) were detected from IMS32 cells by RT-PCR. In these, we sequenced the mouse GDNF cDNA coding region and observed 97% and 90% homologies to corresponding rat and human cDNA sequences, respectively. These results indicate that the immortalized Schwann cell line mitotically responds to various growth factors and secretes autocrine and paracrine growth-promoting activities in vitro.

Structure, expression and chromosome mapping of MLZE, a novel gene which is preferentially expressed in metastatic melanoma cells

We isolated a novel gene, termed MLZE, from a B16-BL6 cDNA library after subtraction of B16-F10 mRNA. Expression levels of mouse MLZE (mMLZE) increased in accordance with metastatic ability of B16 melanoma sublines. Human homolog of mMlze (hMlze) contained one leucine zipper structure and two potential nuclear localizing signals. Northern blot analysis of multiple human tissues showed that hMLZE was expressed primarily in trachea and spleen. We mapped the hMLZE gene (by fluorescence in situ hybridization) to 8q24.1 - 2, which contains the c-myc gene and is often amplified in malignant melanoma. Immunohistochemistry revealed that the number of hMlze-positive cases was significantly larger in Clark levels III, IV and V melanomas (6 / 11 = 55%) than in Clark levels I and II melanomas (2 / 15 = 13%). In two cases of hMlze-positive melanomas, the strength of hMlze staining increased substantially in the deep component of the tumor. Considering that melanomas above Clark level II are more metastatic than those below Clark level III, these findings suggested that MLZE is one of the genes whose expression is upregulated during the course of acquisition of metastatic potential in melanoma cells.

Rescue of lesioned adult rat spinal motoneurons by adenoviral gene transfer of glial cell line-derived neurotrophic factor

Glial cell line-derived neurotrophic factor (GDNF) has been shown to protect cranial and spinal motoneurons, that suggests potential uses of GDNF in the treatment of spinal cord injury and motor neuron diseases. We examined neuroprotective effect of human GDNF encoded by an adenovirus vector (AxCAhGDNF) on the death of lesioned adult rat spinal motoneurons. The seventh cervical segment (C7) ventral and dorsal roots and dorsal root ganglia of adult Fisher 344 rats were avulsed, and AxCAhGDNF, AxCALacZ (adenovirus encoding beta-galactosidase gene) or PBS was inoculated in C7 vertebral foramen. One week after the avulsion and treatment with AxCALacZ, the animals showed expression of beta-galactosidase activity in lesioned spinal motoneurons. Animals avulsed and treated with AxCAhGDNF showed intense immunolabeling for GDNF in lesioned spinal motoneurons and expression of virus-induced human GDNF mRNA transcripts in the lesioned spinal cord tissue. Nissl-stained cell counts revealed that the treatment with AxCAhGDNF significantly prevented the loss of lesioned ventral horn motoneurons 2 to 8 weeks after avulsion, as compared to AxCALacZ or PBS treatment. Furthermore, the AxCAhGDNF treatment ameliorated choline acetyltransferase immunoreactivity in the lesioned motoneurons after avulsion. These results indicate that the adenovirus-mediated gene transfer of GDNF may prevent the degeneration of motoneurons in adult humans with spinal cord injury and motor neuron diseases.

miR-509 suppresses brain metastasis of breast cancer cells by modulating RhoC and TNF-α

The median survival time of breast cancer patients with brain metastasis is less than 6 months, and even a small metastatic lesion often causes severe neurological disabilities. Because of the location of metastatic lesions, a surgical approach is limited and most chemotherapeutic drugs are ineffective due to the blood brain barrier (BBB). Despite this clinical importance, the molecular basis of the brain metastasis is poorly understood. In this study, we have isolated RNA from samples obtained from primary breast tumors and also from brain metastatic lesions followed by microRNA profiling analysis. Our results revealed that the miR-509 is highly expressed in the primary tumors, while the expression of this microRNA is significantly decreased in the brain metastatic lesions. MicroRNA target prediction and the analysis of cytokine array for the cells ectopically expressed with miR-509 demonstrated that this microRNA was capable of modulating two genes essential for brain invasion, RhoC and TNFα that affect the invasion of cancer cells and permeability of BBB, respectively. Importantly, high levels of TNFα and RhoC-induced MMP9 were significantly correlated with brain metastasis-free survival of breast cancer patients. Furthermore, the results of our in vivo experiments indicate that miR-509 significantly suppressed the ability of cancer cells to metastasize to the brain. These findings suggest that miR-509 plays a critical role in brain metastasis of breast cancer by modulating the RhoC-TNFα network and that this miR-509 axis may represent a potential therapeutic target or serve as a prognostic tool for brain metastasis.

Adenoviral gene transfer of GDNF, BDNF and TGF beta 2, but not CNTF, cardiotrophin-1 or IGF1, protects injured adult motoneurons after facial nerve avulsion

We examined neuroprotective effects of recombinant adenoviral vectors encoding glial cell line-derived neurotrophic factor (GDNF), brain-derived neurotrophic factor (BDNF), ciliary neurotrophic factor (CNTF), cardiotrophin-1 (CT1), insulin-like growth factor-1 (IGF1), and transforming growth factor-beta2 (TGFbeta2) on lesioned adult rat facial motoneurons. The right facial nerves of adult Fischer 344 male rats were avulsed and removed from the stylomastoid foramen, and adenoviral vectors were injected into the facial canal. Animals avulsed and treated with adenovirus encoding GDNF, BDNF, CNTF, CT1, IGF1 and TGFbeta2 showed intense immunolabeling for these factors in lesioned facial motoneurons, respectively, indicating adenoviral induction of the neurotrophic factors in these neurons. The treatment with adenovirus encoding GDNF, BDNF, or TGFbeta2 after avulsion significantly prevented the loss of lesioned facial motoneurons, improved choline acetyltransferase immunoreactivity and prevented the induction of nitric oxide synthase activity in these neurons. The treatment with adenovirus encoding CNTF, CT1 or IGF1, however, failed to protect these neurons after avulsion. These results indicate that the gene transfer of GDNF and BDNF and TGFbeta2 but not CNTF, CT1 or IGF1 may prevent the degeneration of motoneurons in adult humans with motoneuron injury and motor neuron diseases.

Characterization of the yrbA gene of Bacillus subtilis, involved in resistance and germination of spores

Insertional inactivation of the yrbA gene of Bacillus subtilis reduced the resistance of the mutant spores to lysozyme. The yrbA mutant spores lost their optical density at the same rate as the wild-type spores upon incubation with L-alanine but became only phase gray and did not swell. The response of the mutant spores to a combination of asparagine, glucose, fructose, and KCl was also extremely poor; in this medium yrbA spores exhibited only a small loss in optical density and gave a mixture of phase-bright, -gray, and -dark spores. Northern blot analysis of yrbA transcripts in various sig mutants indicated that yrbA was transcribed by RNA polymerase with sigma(E) beginning at 2 h after the start of sporulation. The yrbA promoter was localized by primer extension analysis, and the sequences of the -35 (TCATAAC) and -10 (CATATGT) regions were similar to the consensus sequences of genes recognized by sigma(E). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of proteins solubilized from intact yrbA mutant spores showed an alteration in the protein profile, as 31- and 36-kDa proteins, identified as YrbA and CotG, respectively, were absent, along with some other minor changes. Electron microscopic examination of yrbA spores revealed changes in the spore coat, including a reduction in the density and thickness of the outer layer and the appearance of an inner coat layer-like structure around the outside of the coat. This abnormal coat structure was also observed on the outside of the developing forespores of the yrbA mutant. These results suggest that YrbA is involved in assembly of some coat proteins which have roles in both spore lysozyme resistance and germination.

Antisense oligodeoxyribonucleotides inhibit the expression of the gene for hepatitis B virus surface antigen

The effect of a series of antisense oligodeoxyribonucleotide [oligo(dN)] on the expression of the surface antigen (HBsAg) gene of human hepatitis B virus (HBV) was examined using hepatocellular carcinoma cells that contain integrated HBV genomes. Of a number of antisense oligo(dN)s tested, synthetic 15-mers directed at the cap site of mRNA and regions of the translational initiation site of the HBsAg gene were found to be highly effective and inhibited viral gene expression by as much as 96%. The inhibition was specific to the HBsAg gene and appeared to be at the level of translation. These results suggest a therapeutic potential for antisense oligo(dN) in the treatment of patients who are chronically infected with HBV.

Intraventricular administration of recombinant adenovirus to neonatal twitcher mouse leads to clinicopathological improvements

Twitcher mouse is a murine model of human globoid cell leukodystrophy (Krabbe disease), which is characterized by a genetic deficiency in galactocerebrosidase (GALC) activity. The nervous system is affected early and severely by demyelination in the white matter. So far, there is no effective treatment for Krabbe disease except bone marrow transplantation (BMT). However, BMT has inherent limitations such as unavailability of donors and graft-versus-host disease. In this study, we injected recombinant adenovirus encoding GALC into the lateral ventricle of twitcher mice at postnatal day 0 (PND 0) and the therapeutic effects were evaluated. Our results showed slight, but significant improvements in motor functions, body weight and twitching and a prolonged life span. In brain, GALC activity was increased to 15% that of normal littermates and psychosine concentration was decreased to 55% that of untreated twitcher mice at PND 15. The number of PAS-positive globoid cells in brain stem was also reduced significantly at PND 35. In contrast, when adenoviruses were injected to the twitcher mice at PND 15, almost no improvements were observed. These results demonstrate that the timing of treatment may be of great importance in Krabbe disease.

Cloning and sequencing of the genes involved in the conversion of 5-substituted hydantoins to the corresponding L-amino acids from the native plasmid of Pseudomonas sp. strain NS671

Pseudomonas sp. strain NS671, which produces L-amino acids asymmetrically from the corresponding racemic 5-substituted hydantoins, harbored a plasmid of 172 kb. Curing experiments suggest that this plasmid, designated pHN671, is responsible for the conversion of 5-substituted hydantoins to their corresponding L-amino acids by strain NS671. DNA fragments containing the genes involved in this conversion were cloned from pHN671 in Escherichia coli by using pUC18 as a cloning vector. The smallest recombinant plasmid, designated pHPB12, contained a 7.5-kb insert DNA. The nucleotide sequence of the insert DNA was determined, and three closely spaced open reading frames predicted to encode peptides with molecular masses of 75.6, 64.9, and 45.7 kDa were found. These open reading frames were designated hyuA, hyuB, and hyuC, respectively. Cell extracts from E. coli carrying deletion derivatives of pHPB12 were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the gene products of hyuA, hyuB, and hyuC were identified. The functions of these gene products were also examined with the deletion derivatives. The results indicate that both hyuA and hyuB are involved in the conversions of D- and L-5-substituted hydantoins to corresponding N-carbamyl-D- and N-carbamyl-L-amino acids, respectively, and that hyuC is involved in the conversion of N-carbamyl-L-amino acids to L-amino acids.

Regulation of breast tumorigenesis through acid sensors

The low extracellular pH in the microenvironment has been shown to promote tumor growth and metastasis; however, the underlying mechanism is poorly understood. Particularly, little is known how the tumor cell senses the acidic signal to activate the acidosis-mediated signaling. In this study, we show that breast cancer cells express acid-sensing ion channel 1 (ASIC1), a proton-gated cation channel primarily expressed in the nervous system. RNA interference, knockout and rescue experiments demonstrate a critical role for ASIC1 in acidosis-induced reactive oxidative species and NF-κB activation, two key events for tumorigenesis. Mechanistically, ASIC1 is required for acidosis-mediated signaling through calcium influx. We show that as a cytoplasmic membrane protein, ASIC1 is also associated with mitochondria, suggesting that ASIC1 may regulate mitochondrial calcium influx. Importantly, interrogation of the Cancer Genome Atlas breast invasive carcinoma data set indicates that alterations of ASIC1 alone or combined with other 4 ASIC genes are significantly correlated with poor patient survival. Furthermore, ASIC1 inhibitors cause a significant reduction of tumor growth and tumor load. Together, these results suggest that ASIC1 contributes to breast cancer pathogenesis in response to acidic tumor microenvironments, and ASIC1 may serve as a prognostic marker and a therapeutic target for breast cancer.

Elevated lipogenesis in epithelial stem-like cell confers survival advantage in ductal carcinoma in situ of breast cancer

Upregulation of lipogenesis is a hallmark of cancer and blocking the lipogenic pathway is known to cause tumor cell death by apoptosis. However, the exact role of lipogenesis in tumor initiation is as yet poorly understood. We examined the expression profile of key lipogenic genes in clinical samples of ductal carcinoma in situ (DCIS) of breast cancer and found that these genes were significantly upregulated in DCIS. We also isolated cancer stem-like cells (CSCs) from DCIS.com cell line using cell surface markers (CS24(-)CD44(+)ESA(+)) and found that this cell population has significantly higher tumor-initiating ability to generate DCIS compared with the non-stem-like population. Furthermore, the CSCs showed significantly higher level of expression of all lipogenic genes than the counterpart population from non-tumorigenic breast cancer cell line, MCF10A. Importantly, ectopic expression of SREBP1, the master regulator of lipogenic genes, in MCF10A significantly enhanced lipogenesis in stem-like cells and promoted cell growth as well as mammosphere formation. Moreover, SREBP1 expression significantly increased the ability of cell survival of CSCs from MCF10AT, another cell line that is capable of generating DCIS, in mouse and in cell culture. These results indicate that upregulation of lipogenesis is a pre-requisite for DCIS formation by endowing the ability of cell survival. We have also shown that resveratrol was capable of blocking the lipogenic gene expression in CSCs and significantly suppressed their ability to generate DCIS in animals, which provides us with a strong rationale to use this agent for chemoprevention against DCIS.

Assembly and genetics of spore protective structures

The sporulation program in Bacillus subtilis ends in the formation of a highly resistant endospore that can withstand extremes of heat, mechanical disruption, ultraviolet irradiation, lytic enzymes and chemical attack. These properties are attributed mainly to the unique structure of spore coat and cortex, as well as to the physical state of the spore cytoplasm. The outermost layer of the spore, called the coat, has two morphologically distinct sublayers: an electron-dense outer coat and an electron-translucent inner coat. The coat is composed of more than 2 dozen proteins of varying size. Many coat genes and coat proteins have been isolated and characterized in detail, and studies of these have identified proteins with important roles in coat assembly, resistance and spore germination. We describe here characteristics of the coat proteins and propose a model for coat assembly based on recent work.

Transplantation of human sympathetic neurons and adrenal chromaffin cells into parkinsonian monkeys: no reversal of clinical symptoms

Cultured human fetal sympathetic ganglion explants or adrenal chromaffin cell aggregates were implanted into the left striatum of monkeys whose left nigrostriatal pathway had been lesioned with the neurotoxin MPTP. There was no clinical reversal of parkinsonian symptoms and PET scans did not show increased striatal fluorodopa uptake from pre-implant levels. At sacrifice, left striatal contents of dopamine were not statistically different from MPTP-treated but non-implanted controls. Histological examinations revealed pockets of extrinsic cells which were found at the end of needle tracks. There was no evidence of immune rejection. The extrinsic cells did not stain for tyrosine hydroxylase or neurofilament, suggesting that they were not dopaminergic neurons. The failure to reverse clinical parkinsonian symptoms highlights the stage of infancy of neural implantation in Parkinson's disease.

Adenovirus-mediated transduction with human glial cell line-derived neurotrophic factor gene prevents 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced dopamine depletion in striatum of mouse brain

As a novel trial of neuroprotective therapy of neurodegenerative diseases, we have constructed a recombinant adenovirus vector (rAdv) bearing a neurotrophic factor gene to deliver the factor to rescue neurons in vivo. In the present study, human glial cell line-derived neurotrophic factor (hGDNF) was chosen to examine the applicability of our strategy to a mouse model of Parkinson's disease. During the construction of the rAdv, we found that the strong constitutive hGDNF expression unit somehow inhibited the appearance of the rAdv. Therefore we adopted a self-contained tetracycline-regulated expression system to acquire an rAdv expressing hGDNF. By analyzing the condition medium of SH-SY5Y cells infected with our constructed virus vector, we confirmed that biologically active GDNF was successfully expressed in vitro. For an animal study, we delivered this virus vector directly to the C57 black mouse brain and then exposed the animal to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to injure the nigrostriatal dopaminergic neurons. One week after the MPTP exposure, the neuroprotective effect of the virus vector was estimated by measurement of the dopamine content in the striatum of the mouse brain. The mice that had received our constructed virus had significantly higher dopamine levels in their striatum, demonstrating that our rAdv expressing hGDNF has therapeutic potential to protect the nigrostriatal dopaminergic neurons in vivo.

Establishment of an improved mouse model for infantile neuroaxonal dystrophy that shows early disease onset and bears a point mutation in Pla2g6

Calcium-independent group VIA phospholipase A(2) (iPLA(2)beta), encoded by PLA2G6, has been shown to be involved in various physiological and pathological processes, including immunity, cell death, and cell membrane homeostasis. Mutations in the PLA2G6 gene have been recently identified in patients with infantile neuroaxonal dystrophy (INAD). Subsequently, it was reported that similar neurological impairment occurs in gene-targeted mice with a null mutation of iPLA(2)beta, whose disease onset became apparent approximately 1 to 2 years after birth. Here, we report the establishment of an improved mouse model for INAD that bears a point mutation in the ankyrin repeat domain of Pla2g6 generated by N-ethyl-N-nitrosourea mutagenesis. These mutant mice developed severe motor dysfunction, including abnormal gait and poor performance in the hanging grip test, as early as 7 to 8 weeks of age, in a manner following Mendelian law. Neuropathological examination revealed widespread formation of spheroids containing tubulovesicular membranes similar to human INAD. Molecular and biochemical analysis revealed that the mutant mice expressed Pla2g6 mRNA and protein, but the mutated Pla2g6 protein had no glycerophospholipid-catalyzing enzyme activity. Because of the significantly early onset of the disease, this mouse mutant (Pla2g6-inad) could be highly useful for further studies of pathogenesis and experimental interventions in INAD and neurodegeneration.

Replication of bacteriophage phi 29 DNA in vitro: the roles of terminal protein and DNA polymerase

phi 29 DNA replication is initiated by the formation of a covalent complex between the viral-coded terminal protein and dAMP (TP-dAMP). This initiation reaction system has been reconstituted from two phage-encoded proteins, the terminal protein and DNA polymerase. The phi 29 DNA polymerase was purified from phage-infected cells by using poly(dA) X p(dT)12-18 as an assay template. The purified polymerase has an apparent molecular mass of 68 kDa in its native form and it appears to function as a monomer. The terminal protein was purified to homogeneity from Escherichia coli cells harboring a cloned plasmid that contained a phi 29 gene 3 segment. The molecular mass of the purified terminal protein was about 30 kDa in both the denatured and the native form. The protein apparently functions as a monomer. When the terminal protein and DNA polymerase were incubated in the presence of dATP, Mg2+, and phi 29 DNA-protein as template, the terminal protein bound covalently to dAMP. This reaction did not require ATP. In addition, these two purified fractions catalyzed DNA chain elongation from both ends of phi 29 DNA, yielding the expected 9- to 12-base fragment when assayed in the presence of 2',3'-dideoxycytidine triphosphate. These results indicate that phi 29 DNA polymerase catalyzes formation of the terminal protein-dAMP complex and can also catalyze chain elongation at least 9-12 bases from both ends of phi 29 DNA.

Skeletal muscle regeneration after insulin-like growth factor I gene transfer by recombinant Sendai virus vector

We scrutinized the applicability and efficacy of Sendai virus (SeV) vectors expressing either LacZ or human insulin-like growth factor-I (hIGF-I) in gene transfer into skeletal muscle. Seven days after the intramuscular injection of LacZ/SeV X-gal labeled myofibers were demonstrated in rat anterior tibialis muscle with/without bupivacaine treatment and the transgene expression persisted up to 1 month after injection. Recombinant hIGF-I was detected as a major protein species in culture supernatants of a neonatal rat myoblast cell line L6 and thus induced the cells to undergo myogenetic differentiation. The introduction of hIGF-I/SeV into the muscle showed a significant increase in regenerating and split myofibers which were indicative of hypertrophy, and also an increase in the total number of myofibers, in comparison to that seen in the LacZ/SeV-treated control muscle. These results demonstrate that SeV achieves high-level transgene expression in skeletal muscle, and that hIGF-I gene transfer using SeV vector may therefore have great potential in the treatment of neuromuscular disorders.

Postischemic administration of Sendai virus vector carrying neurotrophic factor genes prevents delayed neuronal death in gerbils

Sendai virus (SeV) vector-mediated gene delivery of glial cell line-derived neurotrophic factor (GDNF) and nerve growth factor (NGF) prevented the delayed neuronal death induced by transient global ischemia in gerbils, even when the vector was administered several hours after ischemia. Intraventricular administration of SeV vector directed high-level expression of the vector-encoded neurotrophic factor genes, which are potent candidates for the treatment of neurodegenerative diseases. After occlusion of the bilateral carotid arteries of gerbils, SeV vector carrying GDNF (SeV/GDNF), NGF (SeV/NGF), brain-derived neurotrophic factor (SeV/BDNF), insulin-like growth factor-1 (SeV/IGF-1) or vascular endothelial growth factor (SeV/VEGF) was injected into the lateral ventricle. Administration of SeV/GDNF, SeV/NGF or SeV/BDNF 30 min after the ischemic insult effectively prevented the delayed neuronal death of the hippocampal CA1 pyramidal neurons. Furthermore, the administration of SeV/GDNF or SeV/NGF as late as 4 or 6 h after the ischemic insult also prevented the death of these neurons. These results indicate that SeV vector-mediated gene transfer of neurotrophic factors has high therapeutic potency for preventing the delayed neuronal death induced by transient global ischemia, and provides an approach for gene therapy of stroke.