👤 Jian Zhou

To develop a new denaturing high performance liquid chromatograph (DHPLC)-based method to screen patients with EXT gene mutation and to study the gene mutation in three families with multiple exostoses. All the exons of EXT gene, including the intro-exon boundaries, were amplified by PCR. Linkage analysis and DHPLC screening were carried out to identify the mutations. DNA sequencing was used to confirm the mutations. Two known splice site mutations, IVS2+1 G to A and IVS7+1 G to T, and two SNPs have been detected in EXT2 or EXT1 gene. The transversions of IVS2+1 G to A and IVS7+1 G to T in EXT2 gene are suggested to be the disease-causing mutations and the DHPLC is a high throughout, sensitive, simple, quick, economical method to screen gene mutation in hereditary multiple exostosis. Show less

Rhabdastrellic acid-A is an isomalabaricane triterpenoid isolated from the sponge Rhabdastrella globostellata from South China Sea. Our previous study indicated that rhabdastrellic acid-A can inhibit the proliferation of many types of tumor cells with minor toxicity. This study was to investigate the apoptosis of human leukemia HL-60 cells induced by rhabdastrellic acid-A and its possible mechanisms. Inhibitory effect of rhabdastrellic acid-A on the proliferation of HL-60 cells was evaluated by MTT assay. DNA fragmentation was analyzed by agarose electrophoresis. Cell morphology was observed under fluorescent microscope. The protein levels of Caspase-3, poly(ADP-ribose) polymerase (PARP), P73, Bcl-2 and Bax were analyzed by Western blot. The expression profile of apoptosis-related genes was analyzed by gene microarray. Reverse transcription-polymerase chain reaction (RT-PCR) was conducted to confirm some altered genes identified by gene microarray. Rhabdastrellic acid-A inhibited the proliferation of HL-60 cells and the 50% inhibition concentration (IC50) was (0.64+/-0.21) microg/ml. When treated with 1 microg/ml rhabdastrellic acid-A for 36 h, condensation of nuclear chromatin of HL-60 cells was observed under fluorescent microscope and DNA fragmentation was observed by agarose electrophoresis. Also, rhabdastrellic acid-A induced cleavage of PARP and Caspase-3. The mRNA levels of 44 genes, including p73, JunD, TNFAIP3 and GADD45A, were up-regulated and the mRNA levels of 16 genes, including MAP2K5 and IGF2R, were down-regulated. The results were further confirmed by RT-PCR. The protein level of P73 was up-regulated after rhabdastrellic acid-A treatment. Rhabdastrellic acid-A could induce the apoptosis of HL-60 cells which may be related to the up-regulation of apoptosis-related genes such as p73 and JunD, and the down-regulation of MAP2K5 and IGF2R. Show less

Previous studies have demonstrated that germinal vesicle of amphibian oocyte contains small nuclear ribonucleoprotein polypeptide C (SNRPC). In this study, a putative member of SNRPC was identified from Carassius auratus gibelio oocyte cDNA library. Its full-length cDNA has an open reading frame of 201 nt for encoding a peptide of 66 aa, a short 5'-UTR of 19 nt and a long 3'-UTR of 347 nt including a polyadenylation signal and poly- (A) tail, and the deduced amino acid sequence has 47% identity with the C-terminal of the zebrafish small nuclear ribonucleoprotein polypeptide C. Western blot analysis revealed its oocyte-specific expression. Immunofluorescence localization indicated that its gene product localized to numerous nucleoli within the oocytes and showed dynamic changes with the nucleoli during oocyte maturation. RT-PCR and Western blot analysis further revealed its constant presence in the oocytes and in the embryos until hatching. The data suggested that the newly identified CagOSNRPC might be a nucleolar protein. Show less

Gut hormone gastric inhibitory polypeptide (GIP) stimulates insulin secretion from pancreatic beta-cells upon ingestion of nutrients. Inhibition of GIP signaling prevents the onset of obesity and consequent insulin resistance induced by high-fat diet. In this study, we investigated the role of GIP in accumulation of triglycerides into adipocytes and in fat oxidation peripherally using insulin receptor substrate (IRS)-1-deficient mice and revealed that IRS-1(-/-)GIPR(-/-) mice exhibited both reduced adiposity and ameliorated insulin resistance. Furthermore, increased gene expression of CD36 and UCP2 in liver, and increased expression and enzyme activity of 3-hydroxyacyl-CoA dehydrogenase in skeletal muscle of IRS-1(-/-)GIPR(-/-) mice might contribute to the lower respiratory quotient and the higher fat oxidation in light phase. These results suggest that GIP plays a crucial role in switching from fat oxidation to fat accumulation under the diminished insulin action as a potential target for secondary prevention of insulin resistance. Show less

The recently discovered apolipoprotein A5 ( APOA5 ) gene has been shown to be important in determining plasma triglyceride levels, a major cardiovascular disease risk factor. We searched for possible associations of the APOA5 gene polymorphisms S19W and -1131T>C with coronary heart disease (CHD) in a Chinese population. A total of 483 Chinese CHD patients and 502 control non-CHD subjects were genotyped by polymerase chain reaction-restriction fragment length polymorphism for these 2 single nucleotide polymorphisms. We found that the minor allele 19W was observed only in CHD patients and not in controls, with allelic frequencies of 0.047 and 0.000, respectively ( P < .000001), and the minor allele -1131C was significantly higher in CHD patients than in controls (0.391 vs 0.299, P < .0001). These results suggest that both the S19W and -1131T>C variations in the APOA5 gene are associated with the CHD and appear to be 2 genetic risk factors for CHD susceptibility in Chinese. Moreover, we found that triglyceride levels were significantly higher in -1131C carriers than in -1131T subjects of the control group and that high-density-lipoprotein cholesterol was decreased in -1131C carriers among CHD patients. Show less

A gene coding a novel isoform of carbamyl phosphate synthetase I (CPS1) was cloned from a human testicular library. As shown by cDNA microarray hybridization, this gene was expressed at a higher level in human adult testes than in fetal testes. The full length of its cDNA was 3831 bp, with a 3149 bp open reading frame, encoding a 1050-amino-acid protein. The cDNA sequence was deposited in the GenBank (AY317138). Sequence analysis showed that it was homologous to the human CPS1 gene. The putative protein contained functional domains composing the intact large subunit of carbamoyl phosphate synthetase, thus indicated it has the capability of arginine biosynthesis. A multiple tissue expression profile showed high expression of this gene in human testis, suggesting the novel alternative splicing form of CPS1 may be correlated with human spermatogenesis. Show less

Clinical phenotype of hypertrophic cardiomyopathy exhibits significant inter- and intra-familial heterogeneities. To test if MYBPC3 polymorphism could modify the expression of cardiac hypertrophy, 226 patients with hypertrophic cardiomyopathy and 226 age- and sex-matched controls were recruited according to the diagnostic criteria of WHO. Genotyping was completed by using PCR, restrictive enzyme digestion, and sequencing. Three polymorphisms of MYBPC3 were studied, only the GG genotype at 18443 in exon 30 associated with thicker left ventricular wall (25.2+/-5.9 mm) in patient group, not the AA and AG genotypes (19.0+/-5.0mm, P<0.001). After multiple regression analysis for adjustment of age and sex, the association remained. No difference was found in the genotype distribution between control and patients. Our results point out that GG genotype of MYBPC3 might be a genetic risk factor for the expression of cardiac hypertrophic phenotype in the patients with hypertrophic cardiomyopathy. Show less

To investigate the single nucleotide polymorphism 4 (SNP4) of the apolipoprotein A5 (APOA5) gene possible association with coronary heart disease(CHD) and its distribution of in Chinese Han population. APOA5 SNP4 genotyping was performed using polymerase chain reaction and Hae III restriction fragment length polymorphism analysis. APOA5 allelic frequencies of T, C were 0.435, 0.565 and 0.374, 0.626 in CHD group and control group, respectively. There is significant difference in allele and genotype frequencies between CHD group and control group (P<0.05). The levels of plasma high density lipoprotein in CHD patients with CC genotype were higher than those in CHD patients with other genotypes (P<0.01). The frequencies of T allele and C allele in Chinese was significantly different from those in Caucasians (0.374 vs 0.663, 0.626 vs 0.337, P<0.01). The C allele was much more common in Chinese population. The association is found between the Hae III polymorphism and CHD, There is a significant correlation between the CC genotype of the APOA5 and the levels of plasma high density lipoprotein-cholosteal in the CHD group. Show less

Secretion of gastric inhibitory polypeptide (GIP), a duodenal hormone, is primarily induced by absorption of ingested fat. Here we describe a novel pathway of obesity promotion via GIP. Wild-type mice fed a high-fat diet exhibited both hypersecretion of GIP and extreme visceral and subcutaneous fat deposition with insulin resistance. In contrast, mice lacking the GIP receptor (Gipr(-/-)) fed a high-fat diet were clearly protected from both the obesity and the insulin resistance. Moreover, double-homozygous mice (Gipr(-/-), Lep(ob)/Lep(ob)) generated by crossbreeding Gipr(-/-) and obese ob/ob (Lep(ob)/Lep(ob)) mice gained less weight and had lower adiposity than Lep(ob)/Lep(ob) mice. The Gipr(-/-) mice had a lower respiratory quotient and used fat as the preferred energy substrate, and were thus resistant to obesity. Therefore, GIP directly links overnutrition to obesity and it is a potential target for anti-obesity drugs. Show less

In higher eukaryotes, translation of some mRNAs occurs by internal initiation. It is not known, however, whether this mechanism is used to initiate the translation of any yeast mRNAs. In this report, we identify naturally occurring nucleotide sequences that function as internal ribosome entry sites (IRESes) within the 5' leader sequences of Saccharomyces cerevisiae YAP1 and p150 mRNAs. When tested in the 5' untranslated regions of monocistronic reporter genes, both leader sequences enhanced translation efficiency in vegetatively growing yeast cells. Moreover, when tested in the intercistronic region of dicistronic mRNAs, both sequences were shown to contain IRESes that functioned in living cells. The activity of the p150 leader was much greater than that of the YAP1 leader. The second cistron was not expressed in control dicistronic constructs that lacked these sequences or contained the 5' leader sequence of the CLN3 mRNA in the intercistronic region. Further analyses of the p150 IRES revealed that it contained several nonoverlapping segments that were able independently to mediate internal initiation. These results suggested a modular composition for the p150 IRES that resembled the composition of IRESes contained within some cellular mRNAs of higher eukaryotes. Both YAP1 and p150 leaders contain several complementary sequence matches to yeast 18S rRNA. The findings are discussed in terms of our understanding of internal initiation in higher eukaryotes. Show less

MAP kinases (MAPKs), which control mitogenic signal transduction in all eukaryotic organisms, are inactivated by dual specificity MAPK phosphatases (MKPs). MKP-3, a prototypical MKP, achieves substrate specificity through its N-terminal domain binding to the MAPK ERK2, resulting in the activation of its C-terminal phosphatase domain. The solution structure and biochemical analysis of the ERK2 binding (EB) domain of MKP-3 show that regions that are essential for ERK2 binding partly overlap with its sites that interact with the C-terminal catalytic domain, and that these interactions are functionally coupled to the active site residues of MKP-3. Our findings suggest a novel mechanism by which the EB domain binding to ERK2 is transduced to cause a conformational change of the C-terminal catalytic domain, resulting in the enzymatic activation of MKP-3. Show less

Hereditary multiple exostoses (EXT; MIM 133700) is an autosomal dominant bone disorder. It is genetically heterogeneous with at least three chromosomal loci: EXT1 on 8q24.1, EXT2 on 11p11, and EXT3 on 19p. EXT1 and EXT2, the two genes responsible for EXT1 and EXT2, respectively, have been cloned. Recently, three other members of the EXT gene family, named the EXT-like genes (EXTL: EXTL1, EXTL2, and EXTL3), have been isolated. EXT1, EXT2, and the three EXTLs are homologous with one another. We have identified the intron-exon boundaries of EXTL1 and EXTL3 and analyzed EXT1, EXT2, EXTL1, and EXTL3, in 36 Chinese families with EXT, to identify underlying disease-related mutations in the Chinese population. Of the 36 families, five and 12 family groups have mutations in EXT1 and EXT2, respectively. No disease-related mutation has been found in either EXTL1 or EXTL2, although one polymorphism has been detected in EXTL1. Of the 15 different mutations (three families share a common mutation in EXT2), 12 are novel. Most of the mutations are either frameshift or nonsense mutations (12/15). These mutations lead directly or indirectly to premature stop codons, and the mutations generate truncated proteins. This finding is consistent with the hypothesis that the development of EXT is mainly attributable to loss of gene function. Missense mutations are rare in our families, but these mutations may reflect some functionally crucial regions of these proteins. EXT1 is the most frequent single cause of EXT in the Caucasian population in Europe and North America. It accounts for about 40% of cases of EXT. Our study of 36 EXT Chinese families has found that EXT1 seems much less common in the Chinese population, although the frequency of the EXT2 mutation is similar in the Caucasian and Chinese populations. Our findings suggest a possibly different genetic spectrum of this disease in different populations. Show less

To investigate further the genetic basis of hereditary multiple exostoses (EXT) and provide useful information for gene diagnosis of the disease. Polymerase chain reaction-single strand conformation polymorphism was used to examine the entire coding regions of EXT(1) gene on chromosome 8 and EXT(2) gene on chromosome 11 for mutation in thirty EXT families. Mutations were further identified by sequencing. Two frameshift mutations were identified in two unrelated EXT families. One was the deletion of one base(T) in exon 6 of the EXT(1) gene, and the other was the deletion of four bases (tgtt) in exon 2 of the EXT(2) gene. Both of the mutations resulted in a frameshift and premature termination of translation. EXT is a genetically heterogeneous bone disorder caused by the mutation of EXT tumor suppressor gene. These results could be directly applied in the genetic counseling and prenatal genetic diagnosis of EXT. Show less

We have identified two components of a new protein kinase signaling cascade, MAPK/ERK kinase 5 (MEK5) and extracellular signal-regulated kinase 5 (ERK5). The MEK5 cDNA was isolated by degenerate PCR and encodes a 444-amino acid protein, which has approximately 40% identity to known MEKs. ERK5 was identified by a specific interaction with the MEK5 mutants S311A/T315A and K195M in the yeast two-hybrid system. The proteins were found to interact in an in vitro binding assay as well. ERK5 did not interact with MEK1 or MEK2. ERK5 is predicted to contain 815 amino acids and is approximately twice the size of all known ERKs. The C terminus of ERK5 has sequences which suggest that it may be targeted to the cytoskeleton. Sequences located in the N terminus of MEK5 may be important in coupling GTPase signaling molecules to the MEK5 protein kinase cascade. Both MEK5 and ERK5 are expressed in many adult tissue and are abundant in heart and skeletal muscle. A recombinant GST-ERK5 kinase domain displays autophosphorylation on Ser/Thr and Tyr residues. Show less

The fine specificity of mAb F28C4 to myelin basic protein (MBP), acetyl residues 1-9, has been compared with the previously described specificity of an encephalitogenic T cell clone, PJR-25. F28C4 has been found to express a cross-reactive idiotope (CRI) that is shared with MBP acetyl peptide 1-9-specific TCR. The CRI seems to be located at or near the Ag-combining site of F28C4 and the TCR and, thus, might possibly result from overlapping epitope specificity. We tested the fine epitope specificity of F28C4 by using alanine-substituted peptide analogues and found that residues critical for TCR recognition, Cln3 and Pro6, are also necessary for F28C4 recognition. By using nuclear magnetic resonance, we found that the MBP acetyl peptide 1-9 binds F28C4 in an extended conformation and that the central residues are more tightly bound than the terminal residues, much like the MBP-TCR interaction. Furthermore, sequence homology (75% overall) was found between the regions that contained CDR3 of F28C4 VL and VH and the VDJ junction of the TCR V beta. This homology is not shared by other Ig CDR3 regions and arises, in part, because F28C4 uses an unusual V lambda light chain, V lambda x. Thus, F28C4 shares a CRI with the TCRs, possibly as a result of having similar fine epitope specificity and sequence homology. The anti-CRI mAb can down-modulate experimental allergic encephalomyelitis; thus, it is possible that Abs that are similar to F28C4 may play an important immunoregulatory role in experimental allergic encephalomyelitis in vivo. Show less