Functional analysis for gene silencing suppres- sor of P14 gene of Beet necrotic yellow vein virus and S6 gene of Rice black streak dwarf virus was carried out by agro- in- filtration with recombinant vectors of Potat...Functional analysis for gene silencing suppres- sor of P14 gene of Beet necrotic yellow vein virus and S6 gene of Rice black streak dwarf virus was carried out by agro- in- filtration with recombinant vectors of Potato virus X. The phenotype observation of green fluorescent protein (GFP) expression and Northern blot showed that the gene silencing of gfp transgenic Nicotiana benthamiana induced by ho- mologous sequence was strongly suppressed by the immix- ture infiltration of either the P14 or the S6. In the suppressed plants, the gfp mRNA accumulation was higher than that in the non-suppressed controls and the symptoms caused by PVX infection became more severe, especially the gfp DNA methylation of plant genome was significantly inhabited when co-infiltrated with RBSDV S6 gene. These results sug- gested that these two virus genes were potentially to encode for proteins as RNA silencing suppressors.展开更多
Objective To investigate the relationship between alterations of p16 INK4a and p14 ARF genes and gastric carcinogenesis Methods The tumors and neighboring gastric tissues from 48 patients with gastric ca...Objective To investigate the relationship between alterations of p16 INK4a and p14 ARF genes and gastric carcinogenesis Methods The tumors and neighboring gastric tissues from 48 patients with gastric cancer were studied The homozygous deletion, mutation, methylation of the CpG islands, and mRNA expression of p16 INK4a and p14 ARF genes were assessed by PCR, PCR SSCP, PCR based methylation assay, and RT PCR Results ① The homozygous deletion rate of p16 INK4a and p14 ARF was 35 4% (17/48), and no homozygous deletion was examined in any gastric tissue neighboring the tumor ② There was no point mutation of p16 INK4a and p14 ARF in 31 gastric cancers without homozygous deletion or in the matched gastric tissues adjacent to the tumor ③ Methylation of the CpG islands of p16 INK4a and p14 ARF was detected in 47 9% (23/48) of gastric cancers, while methylation was observed only in 2 of 48 gastric tissues neighboring the cancer with a significant difference ( P <0 01) ④ The loss rate of p16 INK4a mRNA was 47 9% (23/48) in gastric cancer, and the patients of the combined methylation of exons 1α and 2 had a higher loss rate (100%, 6/6) of p16 INK4a mRNA than those of the methylation of the other exons (11 8%, 2/17, P <0 01); the loss rate of p14 ARF mRNA was 45 8%(22/48) in gastric cancer, and patients with the combined methylation of exons 1β and 2 had a higher loss rate (100%, 3/3) of p14 ARF mRNA than those of the methylation of the other exons (15%, 3/20, P <0 05) ⑤ The combined loss of p16 INK4a and p14 ARF mRNAs was examined in 1 (5 6%) of 18 patients of well and moderately differentiated carcinomas, and 11 (36 7%) of 30 patients of poorly and not differentiated carcinomas with a significant difference ( P <0 05) Conclusion p16 INK4a and p14 ARF genes are frequently inactivated by homozygous deletion and methylation of the 5'CpG islands in gastric cancer, which may play 展开更多
A soluble matrix protein P14 with an apparent molecular mass of 14.5 kDa was isolated from fragmented nacre of pearl oysters （Pinctada fucata） treated with 10% NaOH solution to investigate the nacre matrix proteins ...A soluble matrix protein P14 with an apparent molecular mass of 14.5 kDa was isolated from fragmented nacre of pearl oysters （Pinctada fucata） treated with 10% NaOH solution to investigate the nacre matrix proteins and their effect on the CaCO3 crystal. The protein was characterized by gel exclusion chromatography and reversed-phase high performance liquid chromatography after demineralization by 10% acetic acid. The X-ray diffraction pattern of P14 crystals indicates that P14 plays an important role in nacre biomineralization. P14 can induce aragonite formation, stimulate CaCO3 crystal formation, and accelerate aragonite precipitation. Heating of the acid insoluble nacre residue, which was named conchiolin, in 10% sodium dodecyl sulfate solution supplemented with 10% β-mercaptoethanol solution for 10-20 min at about 100℃ gave two other soluble proteins having molecular masses of 19.4 kDa and 25.0 kDa. The present study suggests that these two proteins are linked to the insoluble organic matrix by disulfide bridges because the extraction yield increases when β-mercaptoethanol is added to the medium.展开更多
基金This work w as supported by the National Natural Science Founda-tion of China (Grants Nos.30325001 and 30471136).
文摘Functional analysis for gene silencing suppres- sor of P14 gene of Beet necrotic yellow vein virus and S6 gene of Rice black streak dwarf virus was carried out by agro- in- filtration with recombinant vectors of Potato virus X. The phenotype observation of green fluorescent protein (GFP) expression and Northern blot showed that the gene silencing of gfp transgenic Nicotiana benthamiana induced by ho- mologous sequence was strongly suppressed by the immix- ture infiltration of either the P14 or the S6. In the suppressed plants, the gfp mRNA accumulation was higher than that in the non-suppressed controls and the symptoms caused by PVX infection became more severe, especially the gfp DNA methylation of plant genome was significantly inhabited when co-infiltrated with RBSDV S6 gene. These results sug- gested that these two virus genes were potentially to encode for proteins as RNA silencing suppressors.
文摘Objective To investigate the relationship between alterations of p16 INK4a and p14 ARF genes and gastric carcinogenesis Methods The tumors and neighboring gastric tissues from 48 patients with gastric cancer were studied The homozygous deletion, mutation, methylation of the CpG islands, and mRNA expression of p16 INK4a and p14 ARF genes were assessed by PCR, PCR SSCP, PCR based methylation assay, and RT PCR Results ① The homozygous deletion rate of p16 INK4a and p14 ARF was 35 4% (17/48), and no homozygous deletion was examined in any gastric tissue neighboring the tumor ② There was no point mutation of p16 INK4a and p14 ARF in 31 gastric cancers without homozygous deletion or in the matched gastric tissues adjacent to the tumor ③ Methylation of the CpG islands of p16 INK4a and p14 ARF was detected in 47 9% (23/48) of gastric cancers, while methylation was observed only in 2 of 48 gastric tissues neighboring the cancer with a significant difference ( P <0 01) ④ The loss rate of p16 INK4a mRNA was 47 9% (23/48) in gastric cancer, and the patients of the combined methylation of exons 1α and 2 had a higher loss rate (100%, 6/6) of p16 INK4a mRNA than those of the methylation of the other exons (11 8%, 2/17, P <0 01); the loss rate of p14 ARF mRNA was 45 8%(22/48) in gastric cancer, and patients with the combined methylation of exons 1β and 2 had a higher loss rate (100%, 3/3) of p14 ARF mRNA than those of the methylation of the other exons (15%, 3/20, P <0 05) ⑤ The combined loss of p16 INK4a and p14 ARF mRNAs was examined in 1 (5 6%) of 18 patients of well and moderately differentiated carcinomas, and 11 (36 7%) of 30 patients of poorly and not differentiated carcinomas with a significant difference ( P <0 05) Conclusion p16 INK4a and p14 ARF genes are frequently inactivated by homozygous deletion and methylation of the 5'CpG islands in gastric cancer, which may play
基金Supported by the National High-Tech Research and Development (863) Program of China (No. 2003AA603430) and the National Natural Science Foundation of China (No. 30170723)
文摘A soluble matrix protein P14 with an apparent molecular mass of 14.5 kDa was isolated from fragmented nacre of pearl oysters （Pinctada fucata） treated with 10% NaOH solution to investigate the nacre matrix proteins and their effect on the CaCO3 crystal. The protein was characterized by gel exclusion chromatography and reversed-phase high performance liquid chromatography after demineralization by 10% acetic acid. The X-ray diffraction pattern of P14 crystals indicates that P14 plays an important role in nacre biomineralization. P14 can induce aragonite formation, stimulate CaCO3 crystal formation, and accelerate aragonite precipitation. Heating of the acid insoluble nacre residue, which was named conchiolin, in 10% sodium dodecyl sulfate solution supplemented with 10% β-mercaptoethanol solution for 10-20 min at about 100℃ gave two other soluble proteins having molecular masses of 19.4 kDa and 25.0 kDa. The present study suggests that these two proteins are linked to the insoluble organic matrix by disulfide bridges because the extraction yield increases when β-mercaptoethanol is added to the medium.
