A mutation of OSOTP 51 leads to impairment of photosystem I complex assembly and serious photo-damage in rice.

Gene expression in chloroplasts is regulated by many nuclear-encoded proteins. In this study, we isolated a rice (Oryza sativa subsp. japonica) mutant osotp51 with significant reduction in photosystem I (PSI). The osotp51 is extremely sensitive to light and accumulates a higher level of reactive oxygen species. Its leaves are almost albino when grown at 40 µmol photons/m(2) per s. However, grown at 4 µmol photons/m(2) per s, osotp51 has a similar phenotype to the wild-type. 77K chlorophyll fluorescence analysis showed a blue shift in the highest peak emission from PSI in osotp51. In addition, the level of PSI and PSII dimer is dramatically reduced in osotp51. OSOTP 51 encodes a pentatricopeptide repeats protein, homologous to organelle transcript processing 51 in Arabidopsis. Loss-of-function OSOTP51 affects intron splicing of a number of plastid genes, particularly the ycf3 coding a protein involved in the assembly of PSI complex. OSOTP51 is functionally conserved in higher plants. The mutation of osotp51 indirectly leads to a widespread change in the structure and functions of PSI, results in severe photoinhibition, and finally dies, even when grown under very low light intensity.

Expression of MET and SOX2 genes in non-small cell lung carcinoma with EGFR mutation.

Non-small cell lung carcinoma (NSCLC) is a leading cause of cancer-related deaths. Aberrance of the two oncogenes MET and SOX2 are frequently encountered in NSCLC. Exons 18 through 21 of the EGFR gene were screened and MET and SOX2 immunostaining was conducted to analyze the immunohistological staining of MET and SOX2 and the EGFR mutation status. One hundred and fifty tissue samples were examined including 57 squamous cell carcinomas (SCCs), 80 adenocarcinomas (ADCs), 9 adenosquamous carcinomas (ADSCs) and 4 large cell carcinomas (LCCs). The 32 NSCLCs harboring an EGFR mutation included 28 ADCs, 3 SCCs and 1 ADSC. A higher level of SOX2 expression appeared in NSCLCs without the EGFR mutation compared to those with EGFR mutation (χ2=9.02, P=0.0027). Of the 28 ADCs, 24 (85.7%) with an EGFR mutation showed low level of SOX2 expression. ADCs with deletion in exon 19 overexpressed MET and showed low levels of SOX2. SOX2 expression was inversely correlated to the expression of MET in NSCLC and mainly present in non-mutated NSCLC (r=-0.42, P<0.0001). There was a tendency for SOX2 to be expressed in SCCs and particularly in the part of SCC among ADSCs, whereas MET was mainly expressed in the part of ADC among ADSCs and ADCs. High level of MET and SOX2 expression were respectively demonstrated in ADCs and SCCs; MET activation was accompanied with exon 19 deletion in ADCs. EGFR and MET coordinate to drive tumorigenesis. Detection of the activation of MET and EGFR may be used for targeted drug therapy.

[Analysis on association of glucocorticoid receptor gene polymorphism with steroid-resistance in idiopathic nephrotic syndrome of children].

OBJECTIVE: The nephrotic syndrome is defined by heavy proteinuria, edema, hypoalbuminemia, and hyperlipidemia. Idiopathic nephrotic syndrome (INS) mainly occurs in children, which is generally treated with glucocorticoids. The majority of patients are steroid-sensitive (SSINS) while steroid-resistance occurs in a subset of NS children (SRINS). Although intensive efforts have been undertaken to study the associations between SRINS and renal pathological changes, pharmacokinetics, and the GR density and binding affinity, the mechanisms underlying steroid-resistance are still not elucidated entirely. The authors hypothesized that it might be associated with polymorphisms in the glucocorticoid receptor gene (NR3C1). The study aimed to screen the NR3C1 gene for polymorphisms in genomic DNA samples from SRINS, SSINS children and control group, and to analyze the association of the polymorphisms in the NR3C1 gene and SRINS of children. METHODS: Totally 39 SRINS and 67 SSINS children (81 males and 25 females with the mean age of 7 years) were involved in the study. Umbilical cord blood of 62 normal neonates and peripheral blood of 2 healthy volunteers were selected as controls. Genomic DNA was isolated from peripheral blood lymphocytes of all subjects. All the NR3C1-coding exons and intron-flanking portions were amplified by polymerase chain reaction (PCR). For polymorphism screen, PCR products were analyzed by denaturing high performance liquid chromatography (DHPLC). DNA fragments with aberrant elution profiles were re-amplified and sequenced directly. RESULTS: Twelve aberrant elution profiles were identified with DHPLC in SRINS, SSINS and controls. Among them, 6 previously reported polymorphisms and 6 novel polymorphisms were confirmed by sequencing (198G > A, 200G > A, IVSD-16G > T, 1896C > T, 2166C > T, 2430T > C; novel, 1206C > T, 1374A > G, IVSG-68_IVSG-63delAAAAAA, 2193T > G, IVSH-9C > G, 2382C > T), and 3 groups of SNPs were in complete linkage disequilibrium, which resulted in 3 different haplotypes ([198G > A + 200G > A], [1374A > G + IVSG-68_IVSG-63delAAAAAA + IVSH-9C > G + 2382C > T], [1896C > T + 2166C > T + 2430T > C]). The last two genotypes were first reported. The genotype frequencies of the 2 novel haplotypes were 10.3% vs 1.5% in SRINS and SSINS, and 15.4% vs 7.5% in SRINS and SSINS, respectively. Other polymorphisms were relatively rare detectable both in patients and controls. CONCLUSION: Twelve polymorphisms in the NR3C1 gene were detected with the technique of DHPLC, of which six polymorphisms were identified at the first time. Two types of newly found haplotypes were associated with steroid-resistant idiopathic nephrotic syndrome of children, which might be responsible for steroid-resistance in partial idiopathic nephrotic syndrome of children.