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Jing Jia

Publications and source records attributed to Jing Jia.

12 recordsLinked to original sources
PubMed2024

DNA polymerase delta governs parental histone transfer to DNA replication lagging strand.

Chromatin replication is intricately intertwined with the recycling of parental histones to the newly duplicated DNA strands for faithful genetic and epigenetic inheritance. The transfer of parental histones occurs through two distinct pathways: leading strand deposition, mediated by the DNA polymerase ε subunits Dpb3/Dpb4, and lagging strand deposition, facilitated by the MCM helicase subunit Mcm2. However, the mechanism of the facilitation of Mcm2 transferring parental histones to the lagging strand while moving along the leading strand remains unclear. Here, we show that the deletion of Pol32, a nonessential subunit of major lagging-strand DNA polymerase δ, results in a predominant transfer of parental histone H3-H4 to the leading strand during replication. Biochemical analyses further demonstrate that Pol32 can bind histone H3-H4 both in vivo and in vitro. The interaction of Pol32 with parental histone H3-H4 is disrupted through the mutation of the histone H3-H4 binding domain within Mcm2. Our findings identify the DNA polymerase δ subunit Pol32 as a critical histone chaperone downstream of Mcm2, mediating the transfer of parental histones to the lagging strand during DNA replication.

DNA Polymerase III↗
PubMed2006

Expression of PTEN, p27, p21 and AKT mRNA and protein in human BEL-7402 hepatocarcinoma cells in transplanted tumors of nude mice treated with the tripeptide tyroservatide (YSV).

The tripeptide, tyroservatide (YSV), has been previously shown to have antitumor effects through unknown mechanism. In the current study, we examined whether YSV modulates the protumorigenic PI3K pathway in human BEL-7402 hepatocarcinoma cells. BEL-7402 hepatocarcinoma was transplanted into the subcutaneous tissues of nude mice, and YSV, at varying doses, was administered. RT-PCR and Western blot were used to analyze the expression of PTEN, AKT, p21 and p27. YSV at doses of 80 microg/kg/day, 160 microg/kg/day and 320 microg/kg/day markedly inhibited the growth of human BEL-7402 hepatocarcinoma (p < 0.05). YSV increased mRNA and protein expression of the tumor-suppressor genes, PTEN, p21 and p27, and inhibited the mRNA and protein expression of the oncogene AKT. Furthermore, YSV administration was associated with dephosphorylation of both PTEN (which activates PTEN) and AKT (which inhibits AKT). These results are consistent with the possibility that YSV mediates inhibition of tumor growth through inhibition of the PI3K pathway and suggests that YSV should be explored for use as an antitumor agent for hepatocarcinoma.

Animals↗
PubMed2006

Gene-chip analysis of the effect of tripeptide tyroservatide (YSV) on gene-expression in human hepatocarcinoma BEL-7402 tumors transplanted to nude mice.

Tyroservatide (YSV) is a bioactive tripeptide of tyrosyl-seryl-valine. In this study, we studied the effects of YSV on human hepatocarcinoma BEL-7402 tumors transplanted in BALB/c (nu/nu) nude mice, and gene expression in the tumor cells with gene-chip analysis. Results show that YSV significantly inhibits the growth of transplanted human hepatocarcinoma BEL-7402 in nude mice (n = 12) compared with the control group (P < 0.05); with an inhibition rate of 55% at 320 microg/kg/d. Seven hundred eighty-one genes were different between the YSV group and the control group. Fifty-two genes changed in expression level by onefold or more including 37 downregulated genes and 15 upregulated genes. Probably, YSV exhibits a significant antitumor activity by inhibiting the expression of tumor cells histone genes, then damaging tumor cell chromosome and killing tumor cells.

Animals↗
PubMed2006

[Detecting the DNA polymorphism of human complement component C8A by PCR-SSCP analysis].

OBJECTIVE: The aim of this study is to establish a new method for detecting the DNA polymorphism of human complement component C8A. METHODS: Based on the point mutation (C-->A) of C8A gene in exon3,The genotypes of 98 unrelated individuals from Han population in Chengdu were studied by polymerase chain reaction-single strand conformation polymorphism(PCR-SSCP)analysis followed by DNA sequencing. RESULTS: The genotypes of C8A * AA, C8A * BB and C8A * AB were observed and the distribution of the genotypes frequencies of C8A in Chengdu Han population was in accordance with Hardy-Weinberg equilibrium. CONCLUSION: The method of PCR-SSCP is reliable, rapid, simple and cost-effective in detecting the DNA polymorphism of C8A, and it is valuable for further application in population genetic study and forensic science practice.

Adult↗
PubMed2006

[Preparation and identification of monoclonal antibody against human GST-Rta150 fusion protein from Epstein-Barr virus].

OBJECTIVE: To prepare a monoclonal antibody (mAb) against GST-Rta150 fusion protein from EB virus and identify its characteristics. METHODS: BALB/c mouse was rendered immune by GST-Rta150 fusion protein; after that, the spleen cells of immunized mouse were taken to fuse with SP2/0 myeloma cells by a routine method. Then screening for positive hybridoma cells and subclone. Following that, the hybridoma cells were injected into the peritoneal cavity of BALB/c mouse. The ascites was collected and purified. The prepared mAb was identified by double immunodiffusion method for its subclass; in addition, its titer and specificity were identified by ELISA and Western-blot, respectively. RESULTS: One hybridoma cell line 1A9 which stably secreted mAb against GST-Rta150 fusion protein was obtained. Its Ig subclass belonged to IgG1, the titer degree of the purified mAb being 10(-6). Western-blot analysis showed the mAb could combine with GST-Rta150 fusion protein specially. The titer degree of this hybridoma cell line remained unchanged after frozen in liquid nitrogen (LN) for three months. CONCLUSION: The mAb obtained by this method has powerful specificity and high stability. This work could serve as a foundation on which to study the Rta protein from EB virus and the diagnosis and treatment of EB virus correlated diseases.

Animals↗
PubMed2006

[Effect of methylprednisolone on procollagen type III of rats with acute lung injury].

OBJECTIVE: To observe the effect of methylprednisolone on procollagen type III of rats with acute lung injury (ALI) induced by endotoxin. METHODS: Forty-five rats were randomly divided into three groups: endotoxin group, endotoxin plus methylprednisolone group, and control group, with 15 rats in each group. The model of ALI in rat was reproduced by intravenous injection of endotoxin in the dose of 6 mg/kg. On 1, 3, 14 days after the onset of ALI in rats, total cell number, classification of polymorphonuclear neutrophil (PMN), macrophages and procollagen type III in serum and bronchoalveolar lavage fluid (BALF) were determined by radioimmunology. RESULTS: Total cell number, classification of PMN and macrophages in BALF as well as procollagen type III level in serum and BALF were obviously increased in endotoxin group on the first day, then decreased gradually (all P<0.01). Methylprednisolone inhibited the increase of the above-mentioned parameters (P<0.05 or P<0.01). CONCLUSION: Methylprednisolone can inhibit the increase of the procollagen type III levels in serum and BALF in rats with acute lung injury induced by endotoxin.

Acute Lung Injury↗
PubMed2005

Preliminary investigation of the inhibitory effects of the tyroservaltide (YSV) tripeptide on human hepatocarcinoma BEL-7402.

This study aimed to investigate the inhibitory effect of tyroservaltide (YSV) on the human hepatocarcinoma BEL-7402 transplanted into nude mice and to explore its possible anti-tumor mechanism. Nude mice bearing xenografts of the human BEL-7402 hepatoma were given daily i.p. injections of YSV or saline (as a control) after the tumor were transplanted. Calculating tumor volume and measuring tumor weight determined the extent of inhibition of xenografts. The ultrastructure of tumor cells was observed by electron microscopy. Proliferating cell nuclear antigen (PCNA) expression in tissues of the YSV-treated group was observed by immunohistochemistry. Apoptosis of tumor tissue cells was assayed by the terminal transferase uridyl nick end labeling (TUNEL) method. At doses of 80 microg/kg/d and 160 microg/kg/d, YSV could significantly inhibit growth of tumors transplanted into nude mice, with inhibition rates of 60% and 64%, respectively, compared with that of the controls (P < 0.05). Moreover, YSV changed the ultrastructure of tumor cells, resulting in necrosis and apoptosis of the tumor cells. Compared with the saline group, the expression of PCNA in tumor tissue decreased and the count of apoptotic cell increased. Therefore, YSV can significantly inhibit the growth of human hepatocarcinoma BEL-7402 in nude mice, decrease the expression of PCNA in tumor tissue, and induce tumor cell apoptosis.

Animals↗
PubMed2005

The effect of tripeptide tyroserleutide (YSL) on animal models of hepatocarcinoma.

This study aimed to observe the effects of tyroserleutide (tyrosyl-seryl-leucine, YSL) on the survival time of mice transplanted with the ascitic fluid-type hepatocarcinoma H22, as well as the inhibitory effect of tyroserleutide on the human hepatocarcinoma Bel-7402 that was transplanted into nude mice. At doses of 80, 20 and 5 microg/kg/d, tyroserleutide significantly prolonged the survival of mice transplanted with H22 tumor cells, producing survival rates of 89%, 39% and 49%, respectively, which were statistically significantly different from the saline group (P < 0.05). YSL, at doses of 80, 160 and 320 microg/kg/d significantly inhibited the growth of the human hepatocarcinoma Bel-7402 tumor in nude mice, producing inhibition of 40%, 64% and 59%, respectively; this inhibition was significantly greater than that by saline (P < 0.05). HE staining and electron microscopy of the pathological changes of the tumor in nude mice showed that YSL changed the structure Bel-7402 tumor cells that were transplanted into nude mice, and also induced tumor cell apoptosis and necrosis, which could be a mechanism by which YSL inhibits the tumor growth in animal models.

Animals↗
PubMed2005

Experimental study of the inhibition of human hepatocarcinoma Bel7402 cells by the tripeptide tyroserleutide(YSL).

PURPOSE: To investigate the antitumor effects of tyroserleutide (tyrosyl-seryl-leucine, YSL) on human Bel7402 hepatocarcinoma in vitro and in vivo, with preliminary exploration of its antitumor mechanism. METHODS: MTT was used to observe the anticarcinogenic effects of YSL on human hepatocarcinoma Bel7402 cells in vitro. The ultrastructure of tumor cells was observed by electron microscopy. Nude mice bearing xenografts of human hepatocarcinoma Bel7402 were given daily i.p. injections of YSL or saline and an admixture of amino acids as controls, after tumor implantation. The inhibition of xenografts was determined by calculating the tumor volume and measuring tumor weight. The effects of YSL on the cell cycle and apoptosis of Bel7402 cells were determined by flow cytometry, and the effects on the ultrastructure of the cells by electron microscopy. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) and proliferating-cell nuclear antigen (PCNA) immunohistochemical staining were used to investigate apoptosis in tumor tissue in nude mice. RESULTS: In vitro YSL inhibited the proliferation of human Bel7402 tumor cells and changed their ultrastructure, resulting in the necrosis and apoptosis of the tumor cells. YSL at 80, 160, or 320 microg/kg/d inhibited tumor growth in nude mice by 40.26, 64.17, and 59.19%, respectively, which are significantly lower than the inhibition exerted by saline and an admixture of YSL amino acids (P<0.05). The ultrastructure and cell cycle of human hepatocarcinoma Bel7402 cells were changed by treatment with YSL, with a rate of apoptosis higher than that of the control group. TUNEL and PCNA analysis showed that YSL inhibited the proliferation of tumor cells and induced apoptosis at the level of the cell. CONCLUSIONS: YSL significantly inhibited human hepatocarcinoma Bel7402 growth in vitro and in vivo. The growth inhibition of the tumor may involve necrosis and apoptosis of the tumor induced by YSL.

Animals↗
PubMed2005

[Expression and purification of GST-Rta fusion protein from EB virus and preparation of the polyclonal antibody against GST-Rta].

OBJECTIVE: To obtain the recombinant fusion proteins GST-Rta185 and GST-Rta150 from EB virus and prepare two Rta protein specific polyclonal antibodies, respectively. METHODS: Plasmids pGEX-R1501, pGEX-R1851 and pGEX-5X-3 were separately transformed into Escherichia coli BL21 (DE3). Expressions of the recombinant proteins R150-GST, R185-GST and free GST were induced by 0.1 mmol/L IPTG in LB medium. The expressed proteins were purified from lysates with Glutathione Sepharose 4B. Purified proteins were mixed with Freund's adjuvant and then were used to immunize rabbits. RESULTS: High levels of expression of target proteins were detected in the lysates and the purified proteins were obtained by affinity chromatography with Glutathione Sepharose 4B. Western blot and ELISA analysis suggested that the polyclonal antibodies against GST-R185 and GST-R150 were specific. CONCLUSION: The antiserums have good specificity. They are important for the research on Rta fusion proteins from EB virus and for the diagnosis or treatment of EB virus associated diseases.

Animals↗
PubMed2002

Dominance of pressure natriuresis in acute depressor responses to increased renal artery pressure in rabbits and rats.

Increasing renal artery pressure (RAP) activates pressure diuresis/natriuresis and inhibits renal renin release. There is also evidence that increasing RAP stimulates release of a putative depressor hormone from the renal medulla, although this hypothesis remains controversial. We examined the relative roles of these antihypertensive mechanisms in the acute depressor responses to increased RAP in anaesthetized rabbits and rats. In rabbits, an extracorporeal circuit was established which allows RAP to be set and controlled without direct effects on systemic haemodynamics. When RAP was maintained at approximately 65 mmHg, cardiac output (CO) and mean arterial pressure (MAP) did not change significantly. In contrast, when RAP was increased to approximately 160 mmHg, CO and MAP fell 20 +/- 5 % and 36 +/- 5 %, respectively, over 30 min. Urine flow also increased more than 28-fold when RAP was increased. When compound sodium lactate was infused intravenously at a rate equal to urine flow, neither CO nor MAP fell significantly in response to increased RAP. In 1 kidney-1 clip hypertensive rats, MAP fell by 54 +/- 10 mmHg over a 2 h period after unclipping. In rats in which isotonic NaCl was administered intravenously at a rate equal to urine flow, MAP did not change significantly after unclipping (-14 +/- 9 mmHg). Our results suggest that the depressor responses to increasing RAP in these experimental models are chiefly attributable to hypovolaemia secondary to pressure diuresis/natruresis. These models therefore appear not to be bioassays for release of a putative renal medullary depressor hormone.

Animals↗