CMT2Q-causing mutation in the Dhtkd1 gene lead to sensory defects, mitochondrial accumulation and altered metabolism in a knock-in mouse model.

Charcot-Marie-Tooth disease (CMT) is a group of inherited neurological disorders of the peripheral nervous system. CMT is subdivided into two main types: a demyelinating form, known as CMT1, and an axonal form, known as CMT2. Nearly 30 genes have been identified as a cause of CMT2. One of these is the 'dehydrogenase E1 and transketolase domain containing 1' (DHTKD1) gene. We previously demonstrated that a nonsense mutation [c.1455 T > G (p.Y485*)] in exon 8 of DHTKD1 is one of the disease-causing mutations in CMT2Q (MIM 615025). The aim of the current study was to investigate whether human disease-causing mutations in the Dhtkd1 gene cause CMT2Q phenotypes in a mouse model in order to investigate the physiological function and pathogenic mechanisms associated with mutations in the Dhtkd1 gene in vivo. Therefore, we generated a knock-in mouse model with the Dhtkd1Y486* point mutation. We observed that the Dhtkd1 expression level in sciatic nerve of knock-in mice was significantly lower than in wild-type mice. Moreover, a histopathological phenotype was observed, reminiscent of a peripheral neuropathy, including reduced large axon diameter and abnormal myelination in peripheral nerves. The knock-in mice also displayed clear sensory defects, while no abnormalities in the motor performance were observed. In addition, accumulation of mitochondria and an elevated energy metabolic state was observed in the knock-in mice. Taken together, our study indicates that the Dhtkd1Y486* knock-in mice partially recapitulate the clinical phenotypes of CMT2Q patients and we hypothesize that there might be a compensatory effect from the elevated metabolic state in the knock-in mice that enables them to maintain their normal locomotor function.

Research progress of myosin heavy chain genes in human genetic diseases.

Myosins constitute a large superfamily proteins, which convert chemical energy, through ATP hydrolysis, to mechanical force for diverse cellular movements, such as cell migration and muscle contraction. The class Ⅱ myosin forms the filaments in muscle and non-muscle cells as a hexameric protein complex, consisting of two myosin heavy chain (MyHC) subunits and two pairs of non-identical light chain subunits. There are several MyHC isoforms encoded by different genes of the MYH family in humans. At present, distinct mutations in different genes of the MYH family are associated with various human genetic diseases. Mutations in MYH2 are associated with skeletal myopathies, characterized by ophthalmoplegia. Mutations in MYH3 and MYH8 are associated with distal arthrogryposis syndromes. Mutations in MYH7 are associated with not only skeletal muscle diseases, such as Laing distal myopathy and myosin storage myopathy, but also hypertrophic cardiomyopathy. Mutations in MYH9 are associated with the so-called MYH9-related disease, characterized by giant platelets, thrombocytopenia and granulocyte inclusions. In this review, we briefly discuss the expression patterns of the MYH gene family and summarize the research progress in correlating the abnormalities of MYH gene family with various human genetic diseases.

The functional mechanisms and clinical application of read-through drugs.

According to previous reports, nearly one in 10 genetic diseases are caused by nonsense mutations around the world. Nonsense mutations lead to premature transcription terminations in cells, which in turn generate non-functional, truncated proteins. In recent years, read-through drugs are playing increasing prominent roles in the researches related to genetic diseases caused by nonsense mutations. However, due to the fact that the mechanisms lying behind translation termination still remain to be elucidated, the mechanistic research and clinical application of read-through drugs are facing new challenges. This review mainly discusses about the pathogenesis of genetic diseases caused by nonsense mutations, and then introduces the current clinical application of read-through drugs. Finally, we display some problems that remain to be solved and propose some possible coping strategies.

[Advances in genetic studies of Charcot-Marie-Tooth disease type 4 (CMT4)].

The Charcot-Marie-Tooth disease (CMT) is one of the most common human inherited peripheral neuropathies. The most common pattern of inheritance is autosomal dominant, with less often occurrence autosomal recessive and X-linked dominant/recessive inheritance. CMT is generally divided into three forms: demyelinating forms (CMT1), axonal forms (CMT2) and intermediate forms (DI-CMT). The autosomal recessive form (AR-CMT1 or CMT4) is accompanied by progressive distal muscle weakness and atrophy of the limbs, pes cavus and claw-like hands. In addition, CMT4 is also characterized by early onset, rapid progression, and varying degrees of sensory loss and spinal deformities (e.g. scoliosis). Recently, 11 subtypes of CMT4 have been identified. Some of these subtypes were clear in pathogenic mechanisms, some had founder mutation, but some still had limited clinical description and mutation analysis. In this review, we summarize the latest research progresses of CMT4, including genotypes and phenotypes, pathogenic mechanisms and mouse models.

Two nonsense mutations cause protein C deficiency by nonsense-mediated mRNA decay.

INTRODUCTION: Protein C deficiency is a genetic disorder caused by mutations in the protein C gene (PROC). More than 10% of nonsense and frameshift mutations carrying premature termination codons have been identified in PROC, but the exact molecular mechanisms of these mutations on the pathogenesis of protein C deficiency remain unclear. OBJECTIVE: The aim of this study is to investigate whether nonsense-mediated mRNA decay (NMD) can be a mechanism accounting for protein C deficiency. METHODS: PROC of genomic DNA was amplified and sequenced. Recombinant plasmids expressing wild-type (wt) and mutant EGFP-protein C (EGFP-PC) cDNA were constructed and transiently transfected into human embryonic kidney cells using lipofectamine. Expression of mRNAs and proteins of EGFP-PC and NMD factor UPF1 were analyzed by qPCR and Western blot. RESULTS: DNA sequencing revealed a novel heterozygous nonsense mutation (p.Trp247*) in patient 1 and two compound heterozygous mutations (p.Phe181Val and p.Arg199*) in patient 2. Expression studies showed that cells transfected with the mutant plasmids expressed significantly lower levels of EGFP-PC mRNAs and proteins compared to cells transfected with the wt plasmid. A translation inhibitor cycloheximide and UPF1 small interfering RNA (UPF1 siRNA) significantly increased mRNA or protein expression of EGFP-PC in cells transfected with the mutant plasmids. CONCLUSION: Two PROC nonsense mutations (p.Trp247* and p.Arg199*) trigger NMD, resulting in protein C deficiency.

Deletion of Gpr128 results in weight loss and increased intestinal contraction frequency.

AIM: To generate a Gpr128 gene knockout mouse model and to investigate its phenotypes and the biological function of the Gpr128 gene. METHODS: Bacterial artificial chromosome-retrieval methods were used for constructing the targeting vector. Using homologous recombination and microinjection technology, a Gpr128 knockout mouse model on a mixed 129/BL6 background was generated. The mice were genotyped by polymerase chain reaction (PCR) analysis of tail DNA and fed a standard laboratory chow diet. Animals of both sexes were used, and the phenotypes were assessed by histological, biochemical, molecular and physiological analyses. Semi-quantitative reverse transcription-PCR and Northern blotting were used to determine the tissue distribution of Gpr128 mRNA. Beginning at the age of 4 wk, body weights were recorded every 4 wk. Food, feces, blood and organ samples were collected to analyze food consumption, fecal quantity, organ weight and constituents of the blood and plasma. A Trendelenburg preparation was utilized to examine intestinal motility in wild-type (WT) and Gpr128(-/-) mice at the age of 8 and 32 wk. RESULTS: Gpr128 mRNA was highly and exclusively detected in the intestinal tissues. Targeted deletion of Gpr128 in adult mice resulted in reduced body weight gain, and mutant mice exhibited an increased frequency of peristaltic contraction and slow wave potential of the small intestine. The Gpr128(+/+) mice gained more weight on average than the Gpr128(-/-) mice since 24 wk, being 30.81 ± 2.84 g and 25.74 ± 4.50 g, respectively (n = 10, P < 0.01). The frequency of small intestinal peristaltic contraction was increased in Gpr128(-/-) mice. At the age of 8 wk, the frequency of peristalsis with an intraluminal pressure of 3 cmH2O was 6.6 ± 2.3 peristalsis/15 min in Gpr128(-/-) intestine (n = 5) vs 2.6 ± 1.7 peristalsis/15 min in WT intestine (n = 5, P < 0.05). At the age of 32 wk, the frequency of peristaltic contraction with an intraluminal pressure of 2 and 3 cmH2O was 4.6 ± 2.3 and 3.1 ± 0.8 peristalsis/15 min in WT mice (n = 8), whereas in Gpr128(-/-) mice (n = 8) the frequency of contraction was 8.3 ± 3.0 and 7.4 ± 3.1 peristalsis/15 min, respectively (2 cmH2O: P < 0.05 vs WT; 3 cmH2O: P < 0.01 vs WT). The frequency of slow wave potential in Gpr128(-/-) intestine (35.8 ± 4.3, 36.4 ± 4.2 and 37.1 ± 4.8/min with an intraluminal pressure of 1, 2 and 3 cmH2O, n = 8) was also higher than in WT intestine (30.6 ± 4.2, 31.4 ± 3.9 and 31.9 ± 4.5/min, n = 8, P < 0.05). CONCLUSION: We have generated a mouse model with a targeted deletion of Gpr128 and found reduced body weight and increased intestinal contraction frequency in this animal model.

Dopamine receptor 3 might be an essential molecule in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced neurotoxicity.

BACKGROUND: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induces Parkinson's disease (PD)-like neurodegeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc) via its oxidized product, 1-methyl-4-phenylpyridinium (MPP+), which is transported by the dopamine (DA) transporter into DA nerve terminals. DA receptor subtype 3 (D3 receptor) participates in neurotransmitter transport, gene regulation in the DA system, physiological accommodation via G protein-coupled superfamily receptors and other physiological processes in the nervous system. This study investigated the possible correlation between D3 receptors and MPTP-induced neurotoxicity. A series of behavioral experiments and histological analyses were conducted in D3 receptor-deficient mice, using an MPTP-induced model of PD. RESULTS: After the fourth MPTP injection, wild-type animals that received 15 mg/kg per day displayed significant neurotoxin-related bradykinesia. D3 receptor-deficient mice displayed attenuated MPTP-induced locomotor activity changes. Consistent with the behavioral observations, further neurohistological assessment showed that MPTP-induced neuronal damage in the SNpc was reduced in D3 receptor-deficient mice. CONCLUSIONS: Our study indicates that the D3 receptor might be an essential molecule in MPTP-induced PD and provides a new molecular mechanism for MPTP neurotoxicity.

A nonsense mutation in DHTKD1 causes Charcot-Marie-Tooth disease type 2 in a large Chinese pedigree.

Charcot-Marie-Tooth (CMT) disease represents a clinically and genetically heterogeneous group of inherited neuropathies. Here, we report a five-generation family of eight affected individuals with CMT disease type 2, CMT2. Genome-wide linkage analysis showed that the disease phenotype is closely linked to chromosomal region 10p13-14, which spans 5.41 Mb between D10S585 and D10S1477. DNA-sequencing analysis revealed a nonsense mutation, c.1455T>G (p.Tyr485(∗)), in exon 8 of dehydrogenase E1 and transketolase domain-containing 1 (DHTKD1) in all eight affected individuals, but not in other unaffected individuals in this family or in 250 unrelated normal persons. DHTKD1 mRNA expression levels in peripheral blood of affected persons were observed to be half of those in unaffected individuals. In vitro studies have shown that, compared to wild-type mRNA and DHTKD1, mutant mRNA and truncated DHTKD1 are significantly decreased by rapid mRNA decay in transfected cells. Inhibition of nonsense-mediated mRNA decay by UPF1 silencing effectively rescued the decreased levels of mutant mRNA and protein. More importantly, DHTKD1 silencing was found to lead to impaired energy production, evidenced by decreased ATP, total NAD(+) and NADH, and NADH levels. In conclusion, our data demonstrate that the heterozygous nonsense mutation in DHTKD1 is one of CMT2-causative genetic alterations, implicating an important role for DHTKD1 in mitochondrial energy production and neurological development.

[Nonsense-mediated mRNA decay and human monogenic disease].

Nonsense-mediated mRNA decay (NMD) is a widespread quality control mechanism in eukaryotic cells. It can recognize and degrade aberrant transcripts harbouring a premature translational termination codon (PTC), and thereby prevent the production of C-terminally truncated proteins which might be deleterious. Approximately, 30% of human genetic diseases are caused by transcripts containing PTCs. These transcripts are potential targets of NMD. As for monogenic diseases, NMD has effects on the phenotype or mode of inheritance. Here, we explain the mechanism of this surveillance pathway, and take several neuromuscular disorders as examples to discuss its influence for human monogenic diseases. The deeper understanding for NMD will shed light on the nosogenesis and therapies of monogenic diseases.

Germinal Cell Aplasia in Kif18a Mutant Male Mice Due to Impaired Chromosome Congression and Dysregulated BubR1 and CENP-E.

Chromosomal instability during cell division frequently causes cell death or malignant transformation. Orderly chromosome congression at the metaphase plate, a paramount process to vertebrate mitosis and meiosis, is controlled by a number of molecular regulators, including kinesins. Kinesin-8 (Kif18A) functions to control mitotic chromosome alignment at the mid-zone by negative regulation of kinetochore oscillation. Here the authors report that disrupting Kif18a function results in complete sterility in male but not in female mice. Histological examination reveals that Kif18a(-/-) testes exhibit severe developmental impairment of seminiferous tubules. Testis atrophy in Kif18a(-/-) mice is caused by perturbation of microtubule dynamics and spindle pole integrity, leading to chromosome congression defects during mitosis and meiosis. Depletion of KIF18A via RNAi causes mitotic arrest accompanied by unaligned chromosomes and increased microtubule nucleating centers in both GC-1 and HeLa cells. Prolonged depletion of KIF18A causes apoptosis due to perturbed microtubule dynamics. Further studies reveal that KIF18A silencing results in degradation of CENP-E and BubR1, which is accompanied by premature sister chromatid separation. KIF18A physically interacts with BubR1 and CENP-E, and this interaction is modulated during mitosis. Combined, the studies indicate that KIF18A is essential for normal chromosome congression during cell division and that the absence of KIF18A function causes severe defects in microtubule dynamics, spindle integrity, and checkpoint activation, leading to germinal cell aplasia in mice.

Target deletion of the cytoskeleton-associated protein palladin does not impair neurite outgrowth in mice.

Palladin is an actin cytoskeleton-associated protein which is crucial for cell morphogenesis and motility. Previous studies have shown that palladin is localized to the axonal growth cone in neurons and may play an important role in axonal extension. Previously, we have generated palladin knockout mice which display cranial neural tube closure defect and embryonic lethality before embryonic day 15.5 (E15.5). To further study the role of palladin in the developing nervous system, we examined the innervation of palladin-deficient mouse embryos since the 200 kd, 140 kd, 90-92 kd and 50 kd palladin isoforms were undetectable in the mutant mouse embryo brain. Contrary to the results of previous studies, we found no inhibition of the axonal extension in palladin-deficient mouse embryos. The cortical neurons derived from palladin-deficient mice also showed no significant difference in neurite outgrowth as compared with those from wild-type mice. Moreover, no difference was found in neurite outgrowth of neural stem cell derived-neurons between palladin-deficient mice and wild-type mice. In conclusion, these results suggest that palladin is dispensable for normal neurite outgrowth in mice.

Multiple synostoses syndrome is due to a missense mutation in exon 2 of FGF9 gene.

Fibroblast growth factors (FGFs) play diverse roles in several developmental processes. Mutations leading to deregulated FGF signaling can cause human skeletal dysplasias and cancer.(1,2) Here we report a missense mutation (Ser99Asp) in exon 2 of FGF9 in 12 patients with multiple synostoses syndrome (SYNS) in a large Chinese family. In vitro studies demonstrate that FGF9(S99N) is expressed and secreted as efficiently as wild-type FGF9 in transfected cells. However, FGF9(S99N) induces compromised chondrocyte proliferation and differentiation, which is accompanied by enhanced osteogenic differentiation and matrix mineralization of bone marrow-derived mesenchymal stem cells (BMSCs). Biochemical analysis reveals that S99N mutation in FGF9 leads to significantly impaired FGF signaling, as evidenced by diminished activity of Erk1/2 pathway and decreased beta-catenin and c-Myc expression when compared with wild-type FGF9. Importantly, the binding of FGF9(S99N) to its receptor is severely impaired although the dimerization ability of mutant FGF9 itself or with wild-type FGF9 is not detectably affected, providing a basis for the defective FGFR signaling. Collectively, our data demonstrate a previously uncharacterized mutation in FGF9 as one of the causes of SYNS, implicating an important role of FGF9 in normal joint development.

Disruption of palladin leads to defects in definitive erythropoiesis by interfering with erythroblastic island formation in mouse fetal liver.

Palladin was originally found up-regulated with NB4 cell differentiation induced by all-trans retinoic acid. Disruption of palladin results in neural tube closure defects, liver herniation, and embryonic lethality. Here we further report that Palld(-/-) embryos exhibit a significant defect in erythropoiesis characterized by a dramatic reduction in definitive erythrocytes derived from fetal liver but not primitive erythrocytes from yolk sac. The reduction of erythrocytes is accompanied by increased apoptosis of erythroblasts and partial blockage of erythroid differentiation. However, colony-forming assay shows no differences between wild-type (wt) and mutant fetal liver or yolk sac in the number and size of colonies tested. In addition, Palld(-/-) fetal liver cells can reconstitute hematopoiesis in lethally irradiated mice. These data strongly suggest that deficient erythropoiesis in Palld(-/-) fetal liver is mainly due to a compromised erythropoietic microenvironment. As expected, erythroblastic island in Palld(-/-) fetal liver was found disorganized. Palld(-/-) fetal liver cells fail to form erythroblastic island in vitro. Interestingly, wt macrophages can form such units with either wt or mutant erythroblasts, while mutant macrophages lose their ability to bind wt or mutant erythroblasts. These data demonstrate that palladin is crucial for definitive erythropoiesis and erythroblastic island formation and, especially, required for normal function of macrophages in fetal liver.

Palladin regulates cell and extracellular matrix interaction through maintaining normal actin cytoskeleton architecture and stabilizing beta1-integrin.

Cell and extracellular matrix (ECM) interaction plays an important role in development and normal cellular function. Cell adhesion and cell spreading on ECM are two basic cellular behaviors related to cell-ECM interaction. Here we show that palladin, a novel actin cytoskeleton-associated protein, is actively involved in the regulation of cell-ECM interaction. It was found that palladin-deficient mouse embryonic fibroblasts (MEFs) display decreased cell adhesion and compromised cell spreading on various ECMs. Disorganized actin cytoskeleton architecture characterized by faint stress fibers, less lamellipodia and focal adhesions can account for the weakened cell-ECM interaction in palladin(-/-) MEFs. Furthermore, decreased polymerized filament actin and increased globular actin can be observed in palladin(-/-) MEFs, strongly suggesting that palladin is essential for the formation or stabilization of polymerized filament actin. Elevated phospho-cofilin level and proper responses in cofilin phosphorylation to either Rho signal agonist or antagonist in palladin(-/-) MEFs indicate that disrupted stress fibers in palladin(-/-) MEFs is not associated with cofilin phosphorylation. More interestingly, the protein level of ECM receptor beta1-integrin is dramatically decreased in MEFs lacking palladin. Down-regulation of beta1-integrin protein can be restored by proteasome inhibitor MG-132 treatment. All these data implicate that palladin is essential for cell-ECM interaction through maintaining normal actin cytoskeleton architecture and stabilizing beta1-integrin protein.

[Cloning and structural analysis of mouse genomic nucleophosmin gene].

Nucleophosmin (NPM) is an abundant nucleolar phosphoprotein. NPM gene involved chromosomal translocations were found in the patients with anaplastic large cell lymphomas (ALCL), myelodysplastic syndrome (MDS), acute myeloid leukemia (AML) and acute promyelocytic leukemia (APL). To generate NPM gene knockout mice and study its biological function in vivo, we screened the lambda phage genomic library derived from 129S1 mice with mouse NPM cDNA probe. A positive phage clone which contained the full-length NPM genomic DNA was obtained and the insert of 15.3 kb genomic DNA in this clone was sequenced with shotgun method. BLAST analysis showed that the sequence of insert are 99.8% identity to that of NPM gene of C57BL/6 mouse strain. Based on the sequence, bioinformatics analysis on genomic structure of NPM and the transcription factor binding sites in the NPM 5' flanking region were performed.

[The relationship between haplotypes of multilocus markers and ankylosing spondylitis].

OBJECTIVE: To investigate the relationship between haplotypes of multilocus markers and ankylosing spondylitis (AS). METHODS: Five families with AS were recruited from Shanghai area. Eleven microsatellite markers around D6S276 were analyzed by Linkage package and by Cyrillic package. RESULTS: Fine linkage analysis showed the significant Lod score values with D6S276 was 3.8821, Lod score values with D6S1691 and D6S1618 near D6S276 were larger than 1.5. The crossover value in 5 pedigrees was 14%. The haplotype analysis showed that the regions between D6S1691 and D6S1618 were associated with AS. CONCLUSION: The regions of D6S1691-D6S276-D6S1618 may harbor a susceptible gene of AS. The specific haplotypes of different pedigrees may play an important role in the presymptomatic diagnosis for AS.

[A genomewide scan for the susceptibility gene loci to ankylosing spondylitis in Chinese Han population].

Ankylosing spondylitis (AS) is a common inflammatory arthritis, with a prevalence of 1@1000-3@1000 in Caucasian and 2@1000 in Chinese population. The recognition of the association of HLA-B27 with AS confirmed the importance of heritable factors in the disease. Whole-genome scans showed that some affected-sibling-pair families with AS not only demonstrated strong linkage to the MHC locus, but also identified other regions with suggestive or stronger linkage on chromosomes 1p, 2q, 9q, 10q, 16q and 19q. In order to localize the regions containing genes that determine susceptibility to AS in Chinese Han population, a genomewide screen was performed in nine Chinese families with AS, including 29 affected individuals. LINKAGE and GENEHUNTER packages were used for parametric (LOD) and non-parametric (NPL) analysis. The significant two-point LOD score value with D6S276 (at 44.9 cM from the 6p terminal) was 3.8821 in parametric analysis. Fine mapping showed LOD scores of D6S1691 (at 42.7 cM) and D6S1618 (at 47.6 cM) around D6S276 were 1.5717 and 2.0056, respectively. Single point NPL score of D6S276, D6S1691 and D6S1618 were 2.6053, 2.7490, 2.0202, respectively, and minimum P value were 0.0072, 0.0047, and 0.0265, respectively. Using multipoint NPL, the maximum LOD score values, NPL score and minimum P value obtained near D6S276 were 5.0623, 3,7561, and 0.000233, respectively. As a result, the strong linkage of the D6S276 with AS was found, the region of D6S1691-D6S276-D6S1618 existed a susceptibility gene of AS. In addition, the LOD scores of D3S1292, D4S1535 and D18S64 were larger than 1.0, so they might be some suggestive linkage markers with AS.

[HUP98-HOXA9 transgenic mice are susceptible to N-ethyl-N-nitrosourea stimulation in leukemogenesis].

OBJECTIVE: In order to investigate the leukemogenic potential of NUP98-HOXA9 fusion gene in vivo. METHODS: Molecular cloning technology was used to construct NUP98-HOXA9 transgenic plasmid and NUP98-HOXA9 transgenic mice were generated. The genotype and phenotype of the NUP98-HOXA9 transgenic mice were analyzed by PCR, RT-PCR and colony-forming assay. The effect of N-ethyl-N-nitrosourea (ENU) stimulation on the transgenic mice was analyzed by peripheral blood count, bone marrow (BM) cells morphology pathological examination. RESULTS: The transgenic expression was detected in 5 independent lines of NUP98-HOXA9 transgenic mice, but no expected phenotypes was found in 2 year follow-up. Upon ENU stimulation, 2 of 10 transgenic mice developed myeloid leukemia, suggesting that NUP98-HOXA9 transgenic mice have increased susceptibility to ENU mutagenesis in leukemogenesis. CONCLUSION: The fusion gene expressed in BM cells of NUP98-HOXA9 transgenic mice. It seems that the expression of the fusion gene is insufficient to trigger leukemogenesis. However, the increased susceptibility to ENU mutagenesis suggests that NUP98-HOXA9 fusion gene might play a potential role in leukemogenesis.

[Development of human myeloid leukemia-like phenotype in NUP98-PMX1 transgenic mice].

OBJECTIVE: In order to investigate the leukemogenic potential of NUP98-PMX1 fusion gene in vivo. METHODS: NUP98-PMX1 transgenic mice were generated, in which the fusion gene was driven by hCG promoter and expressed in myeloid cells at early stage of differentiation. Molecular cloning technology was used to construct NUP98-PMX1 transgenic plasmid. The genotype and phenotype of the NUP98-PMX1 transgenic mice were analyzed by PCR, RT-PCR, peripheral blood count (PBC), bone marrow (BM) cells morphology and pathological examination. RESULTS: NIH3T3 cells transfected with NUP98-PMX1 fusion gene grew faster, formed colonies in soft agar, and developed tumors in 10 inoculated nude mice. Among 8 disordered NUP98-PMX1 transgenic mice, 4 developed myeloid leukemia-like phenotype, including 3 resembling human chronic myeloid leukemia. CONCLUSION: NUP98-PMX1 has oncogenic activity and plays a crucial role in leukemogenesis.

[Genome-wide scanning for susceptibility genes in researches on six HLA-associated diseases].

Six human leucocytic antigen(HLA)-associated diseases, including ankylosing spondylitis, rheumatoid arthritis, multiple sclerosis, systemic lupus erythematosus, type 1 diabetes mellitus and psoriasis, were selected as objects of this review. The characteristics of these diseases in whole-genome scans on susceptibility genes or loci undertaken to date were analyzed and compared. Meanwhile, the potential proposals for dealing with the existing problems were put forward.