Expression of Ferric Chelate Reductase Gene in Citrus junos and Poncirus trifoliataTissues

It has been hypothesized that under iron stress high ferric chelate reductase (FCR) activity in the absorptive root of plants tolerant to iron_deficiency will be induced and result in subsequent Fe 2+ transport across the plasmalemma. The activity of FCR and expression of FCR gene (FRO2) in Citrus junos Sieb. ex Tanaka tolerant to iron_deficiency and Poncirus trifoliata (L.) Raf. susceptible to iron_deficiency were determined to elucidate the physiological difference which causes the different tolerance of the two citrus rootstocks to iron stress. The activity of FCR was detectable in excised roots and was stimulated about 20_times in C. junos and only about 3_times in P. trifoliata under iron deficiency for four weeks. The FRO2 of Arabidopsis was used as a probe, the tissue print technique was used to ascertain the expression of the FCR gene in C. junos and P. trifoliata under iron stress. High_level transcripts were observed in the absorptive root, young green stem as well as new leaf of C. junos under iron stress for two weeks, and the transcripts were accumulated only slightly in P. trifoliata at the same time. The results showed that the obvious increase of FCR activity was an important reason for the tolerance of C. junos to iron_deficiency, and the regulation of FCR activity seemed to be at the transcriptional level, and the expression of FRO2 occurred in the root, stem and leaf.

Expression of the novel gene NM23-H1B in ovarian cancer

Objective:To study the expression of the human novel gene NM23-H1B in ovarian cancer. Methods: Totally 24 samples from patients with epithelial ovarian tumor at different clinical stages and 4 from normal ovaries were examined for NM23-H1B mRNA expression by RT-PCR and Northern blot. Results: All samples expressed NM23-H1B mRNA through RT-PCR, while the level of expression in ovarian tumor was higher than that of normal ovary. The results of Northern blot showed that NM23-H1B was overexpressed in ovarian cancer while lowexpressed in normal ovary or low malignant potential (LMP). The level of expression at early stage cancer(stageⅠand Ⅱ) was higher than those in advanced cancer(stage Ⅲ and Ⅳ). In early stage carcinoma, the expression level was involved in the differentiation of tumor cell, and well-differentiated cancer expressed NM23-H1B mRNA in comparatively higher level. Conclusion: The novel gene NM23-N1B is closely correlated with the ovarian cancer.

Expression of JunB Induced by X-rays in Mice

Objective To explore JunB gene expression in spleen cells of mice after the whole body irradiation as well as in normal hematopoietic and leukemia cells in the primary culture after different dosages of X-ray irradiation. Methods Spleen cells were isolated from the mice irradiated with 3 Gy X-rays. Primary cultured cells from mice were incubated in different intervals after X-irradiation at different dosages. Total RNA was extracted from the cells and the fluctuation of JunB mRNA level was assessed by the RNA ratio of JunB/b-actin measured by quantitative Northern blot hybridization. Results After the mice were exposed to 3 Gy X-rays irradiation, JunB expression in spleen cells was remarkably and rapidly increased, and reached its peak 0.5 h later in C3H/He mice and 1 h later in Balb/c mice. In the primary culture of normal spleen and leukemia cells, JunB mRNA levels increased 30 min after irradiation. The enhanced levels of JunB mRNA were returned to a normal level within 240 min after irradiation. Conclusions JunB gene is responsive to ionizing irradiation and is induced at immediate-early phase after the stimulation. This suggests that the JunB gene plays an important role in the early process of the cells against radiation.