Biomedical subjects

Xue-Fan Gu

Publications and source records attributed to Xue-Fan Gu.

5 recordsLinked to original sources

PubMed2004

[Alteration of gene expression profiles of cultured embryo rat cortex induced by phenylalanine].

To have more insight into the mechanism of neuronal injury in phenylketonuria patients, gene expression profiles were studied in cell culture of embryonic rat cortical neurons induced by phenylalanine. Randomly chosen cortical cultures for 3 d were treated by 0.9 mmol/L phenylalanine for 12 h. Control group of the same batch was treated with the same volume of medium. Total RNA was extracted and hybridized with the Affymetrix gene chip U34 according to the protocol provided by the Affymetrix Company. Real-time PCR was used to further confirm the result. We found that the hybridization signals of 167 genes were increased among the total 1323 probes plotted on the chip. The 167 increased genes could be functionally categorized into signal transduction, neuron related, cytoskeleton, metabolism, ion channels, transcription factors, cytokines, and apoptosis related. Signals of 7 probes were decreased, which accounted to 0.5% of the total number. A series of genes that were not reported before were up-regulated by phenylalanine, including Ca(2+)/calmodulin-dependent protein kinase, Brain type II (CaMK II), Ras, P38 MAP kinase, L-voltage dependent calcium channel, some genes related to vesicle formation and transmitter release, some glutamate receptor subunits and glutamate transporters. According to the gene expression profile, it is likely that multi-processes are involved in the neuronal injury induced by high phenylalanine, such as the activation of the NMDR-Ca(2+)- CaMK II - Ras- P38 axis, the abnormality in neurotransmitter release. Our study also suggests that the excitatory neurotransmitter glutamate may play a role in the neural pathology of phenylketonuria.

Animals↗

PubMed2004

Correlation of ATP7B genotype with phenotype in Chinese patients with Wilson disease.

AIM: To determine the mutational characterization of P-type ATP7B gene and to explore the correlation of ATP7B genotype to phenotype in Chinese patients with Wilson disease (WD). METHODS: Seventy-five patients with WD from 72 no-kinship families, 44 males and 31 females, were enrolled in this study. The age of onset ranged from 4 to 39 years, <=18 years in 72 patients. Some exons of ATP7B gene mutations were analyzed in patients with WD by using biochemical methods, polymerase chain reaction-single strand configuration polymorphism (PCR-SSCP) and DNA sequence analysis. A total of 778 coding regions were identified with restriction enzyme Msp I. The activity of Cu-ATPase was assessed by measuring inorganic phosphorus. RESULTS: Sixty-six of 75 patients (88%) had with hepatic manifestations, 39 of them had only hepatic manifestations, 27 patients had hepatic and neurological manifestations or other symptoms at the same time (16 patients had associated neurological manifestation, 3 patients had osteopathy, 8 patients had other symptoms). Eight of the 75 patients (10.7%) had only neurological symptoms, one patient (5 years old) had no symptom. Twelve changing patterns were detected in ATP7B gene by DNA sequencing, including seven mutations (R778L, C656X, G943D, V1140A, V1106I V1216M and 1384del17), six polymorphisms (IVS4-5t/c, A2495G, C2310G, IVS18+6c/t and IVS20+5a/g). R778L occurred in 49/66 patients (74%) with hepatic manifestations, homozygosis of R778L in 16 patients, heterozygosity of R778L in 33 patients. V1106I mutation of ATP7B gene occurred in 2 patients with delaying onset of clinical symptoms. Cu-ATPase activity of three patients with known mutations (R778L/V1106I/A2495G, R778L/V1216M and R778L/R778L) were determined, and the activity of Cu-ATPase was decreased by 44.55%, 88.23% and 69.49% respectively. CONCLUSION: 1384del17bp is a novel mutation found in WD patients. R778L is the most common mutation of ATP7B gene. There is a correlation between R778L and hepatic manifestations in WD patient.

Adenosine Triphosphatases↗

PubMed2004

[Molecular genetic analysis of congenital lipoid adrenal hyperplasia].

OBJECTIVE: Congenital lipoid adrenal hyperplasia (CLAH) is an autosomal recessive inherited disorder, characterized by deficiency of adrenal and gonadal steroid hormones. Recent studies have shown that mutations in the gene for steroidogenic acute regulatory protein (StAR) cause this most severe genetic disorder in steroid hormone biosynthesis. StAR is a mitochondrial protein promotes cholesterol transfer from outer mitochondrial membrane to the inner mitochondrial membrane, where the cholesterol serves as a substrate for P450scc and initiates steroidogenesis. So far, more than 30 different mutations in the StAR gene have been found in the patients with CLAH from various ethnic groups. None of CLAH patients in the Chinese population has been previously reported. In the present study we analyzed the StAR gene in a Chinese patient with CLAH. METHODS: The patient who was a 19-yr-old phenotypic female, has a 46, XY karyotype. Endocrinological evaluation was performed. Genomic DNA samples were abstracted from the bloods of the patient and his parents. Polymerase chain reaction (PCR), direct DNA sequencing, family analysis and restriction enzyme digestion analysis were used to detect and confirm the mutations of StAR gene. RESULTS: Endocrine evaluation of the patient showed extremely elevated basal concentrations of serum ACTH and gonadotropin and minimal concentration of gonadal steroids. An ACTH stimulation test indicated basal serum dehydroepiandrosterone and 17-hydroxyprogesterone were lower than normal detectable range and had no obvious increase after the ACTH stimulation. Automatic sequencing of 7 exons of the StAR gene with the polymerase chain reaction products of the genomic DNA revealed compound heterozygous for a novel nonsense mutation Q77X in exon 3 and the frameshift mutation 838delA in exon 6. The father carried Q77X mutation and the mother carried 838delA mutation. The restriction enzyme site of the Q77X mutation was examined by endonucleotidase BfaI. Furthermore, this mutation was not found in a series of 20 alleles of normal individuals. CONCLUSION: Q77X is the novel mutation found in the patient with CLAH. Q77X and 838delA compound mutations could inactivate the StAR function and give rise to clinically manifest CLAH. This case is the first Chinese patient with CLAH identified by molecular genetic analysis. DNA-based analysis of StAR gene will be helpful for the diagnosis of CLAH.

Adrenal Hyperplasia, Congenital↗

PubMed2002

[Expression of green fluorescent protein vector by promoter sequence of CYP21 gene and CYP21P gene].

After amplification of PCR fragment of -770 bp(-)-1 bp in promoters of CYP21 gene and CYP21P gene respectively, the CMV promoter was cut off from pEGFP-N1, the vectors were constructed, in which contained promoter areas in CYP21 gene (pCYP21) and CYP21P gene (pCYP21P). All pCYP21, pCYP21P, pEGFP-N1(positive control) and negative control were transfected respectively into steroidogenic Y1 cell line, and were observed by inverted fluorescent microscopy and laser confocal microscopy. After transient transfection, the cells placed on inverted fluorescent microscopy. The appearance of GFP expression observed is as follows: pEGFP-N1 at 3 hours; pCYP21 at 7 hours. However, neither pCYP21P nor negative control expressed GFP. Laser confocal microscopy showed that pEGFP-N1 and pCYP21 produced GFP. pEGFP-N1 is stronger than pCYP21, but none of pCYP21P and negative control expressed GFP. Different distribution of GFP in Y1 cell could be seen of pEGFP-N1 and pCYP21, and the intensity of GFP in nucleus is stronger than cytoplasm. Our results further conform that there is a significantly difference of GFP expression in Y1 cell line by promoters of CYP21 and CYP21P.

Animals↗

PubMed2002

[Double stranded RNA (RNA interference RNAi) in different creatures].

Double stranded RNA could degrade mRNA of target gene. It is a useful way for studying gene function. It is used widely in different creatures,such as Arabidopsis thaliana, Caenorhabditis elegans, Drosophila melanogaster, Zebrafish, Mouse. This review is mainly related to the application of dsRNA in recent years.

English Abstract↗