Protein Arginine Methyltransferase 6 (Prmt6) Is Essential for Early Zebrafish Development through the Direct Suppression of gadd45αa Stress Sensor Gene.

Histone lysine methylation is important in early zebrafish development; however, the role of histone arginine methylation in this process remains unclear. H3R2me2a, generated by protein arginine methyltransferase 6 (Prmt6), is a repressive mark. To explore the role of Prmt6 and H3R2me2a during zebrafish embryogenesis, we identified the maternal characteristic of prmt6 and designed two prmt6-specific morpholino-oligos (MOs) to study its importance in early development, application of which led to early epiboly defects and significantly reduced the level of H3R2me2a marks. prmt6 mRNA could rescue the epiboly defects and the H3R2me2a reduction in the prmt6 morphants. Functionally, microarray data demonstrated that growth arrest and DNA damage-inducible, α, a (gadd45αa) was a significantly up-regulated gene in MO-treated embryos, the activity of which was linked to the activation of the p38/JNK pathway and apoptosis. Importantly, gadd45αa MO and p38/JNK inhibitors could partially rescue the defect of prmt6 morphants, the downstream targets of Prmt6, and the apoptosis ratios of the prmt6 morphants. Moreover, the results of ChIP quantitative real time PCR and luciferase reporter assay indicated that gadd45αa is a repressive target of Prmt6. Taken together, these results suggest that maternal Prmt6 is essential to early zebrafish development by directly repressing gadd45αa.

[Roles of matrix metalloproteinases, tissue inhibitor of matrix metalloproteinase and hs-CRP in Kawasaki disease].

OBJECTIVE: To examine the expression of matrix metalloproteinases (MMP)-2, -9, tissue inhibitor of matrix metalloproteinase (TIMP)-1 and hs-CRP, and their relationship with coronary artery in children with Kawasaki disease. METHODS: One hundred and fifty-one children with Kawasaki disease (111 cases with coronary artery damage and 40 cases without) and 60 healthy children were enrolled. The expression of MMP-2, MMP-9 and TIMP-1 was detected using ELISA, and the hs-CRP concentration was measured using the endpoint nephelometry. RESULTS: There were significant differences in the level of MMP-2, MMP-9 and hs-CRP between the patients with or without coronary artery damage and the healthy children (p<0.05). The levels of MMP-2, MMP-9 and hs-CRP were the highest in the cardiovascular damage group (p<0.05). There were positive correlations between MMP-2, MMP-9 and TIMP-1 in children with Kawasaki disease. CONCLUSIONS: MMP-2, MMP-9, TIMP-1 and hs-CRP may play important roles in the development of Kawasaki disease. The combined measurement of MMP-2, MMP-9 and hs-CRP may be useful in the evaluation of the severity in children with Kawasaki disease.

[Choline chloride protects cell membrane and the photosynthetic apparatus in cucumber seedling leaves at low temperature and weak light].

Choline chloride 1.07 mmol/L treatment diminished the saturated lipid contents of the fatty acid components mainly the phosphatidylglycerol (PG) resulting in the decrease of the saturation of lipid (Table 1), declined the permeability of cell membrane and the production of MDA from lipid peroxidation (Fig.2) in the cucumber seedling leaves under low temperature and weak light (6 degrees C, PFD 100 micromol m(-2) s(-1)). Furthermore, the choline chloride treatment alleviated the degradation of chlorophyll pigments especially chlorophyll b, the decrease in maximum photochemical efficiency (Fv/Fm), the capture efficiency of excited energy (Fv'/Fm'), the photochemical quenching coefficient (q(p)) and the actual photochemical efficiency (Phi PSII) of PSII (Table 2, Fig.3A, B & C), and decreases in activity of antioxidant enzymes such as POD, APX and CAT (Fig.4) in chilled leaves under weak light. In addition, choline chloride treatment increased the non-photochemical quenching (NPQ) (Fig.3D) and the proline content (Fig.5) in chilled leaves under weak light. The above results indicate that choline chloride protected the cell membrane and the photosynthetic apparatus in cucumber seedling leaves from chilling stress in weak light.

[Effects of root-applied glycinebetaine on the composition and function of wheat thylakoid membrane under drought stress].

Two wheat cultivars (Triticum aestivum L.), HF9703 tolerant to drought and SN215953 sensitive to drought, were used to study the effects of glycinebetaine on the composition and function of thylakoid membrane. The wheat seedlings with two leaves were pretreated with Hoagland solution containing 1.5 mmol/L glycinebetaine (GB) for 72 h, then cultured with Hoagland solution containing 15% PEG-6000 for 48 h. The seedling leaves were used for mensuration. The results indicated that the chlorophyll, monogalactosyl diaylglycerol (MGDG), digalactosyl diacylglycerol (DGDG) and phosphatidylglycerol (PG) contents of the two wheat cultivars decreased significantly (P<0.05) under drought stress. GB alleviated their decrease. The sulfoquinovosyl diacylglycerol (SQDG) content, trans-hexadecenoic [16:1(3t)] and saturated fatty acid content of MGDG in HF9703 increased significantly (P<0.05), while in SN215953, the sulfoquinovosyl diacylglycerol (SQDG) and trans-hexadecenoic [16:1(3t)] contents decreased significantly under drought stress, but the saturated fatty acid content of MGDG increased slightly. These differences between the two wheat cultivars might account for much of the difference in drought tolerance between them. Ca2+-ATPase activity of thylakoid membrane, Hill-reaction activity and photosynthesis were decreased markedly (P<0.05) by drought stress. GB ameliorated these effects on thylakoid membrane, and the effect of GB on SN215953 was stronger than on HF9703. Discussion was made on the possible mechanism of the alleviating effect of root-applied GB on the composition and function of thylakoid membrane.