SUPPRESSOR OF FRIGIDA 4 cooperates with the histone methylation reader EBS to positively regulate root development.

Maintenance and homeostasis of the quiescent center (QC) in Arabidopsis (Arabidopsis thaliana) root apical meristems are critical for stem cell organization and root development. Despite great progress in relevant research, the molecular mechanisms that determine the root stem cell fate and QC still need further exploration. In Arabidopsis, SUPPRESSOR OF FRIGIDA 4 (SUF4) encodes a C2H2-type zinc finger protein that represses flowering by transcriptional activation of FLOWERING LOCUS C (FLC) through the FRIGIDA (FRI) pathway, and EARLY BOLTING IN SHORT DAYS (EBS) is a bivalent histone reader that prevents premature flowering. Here, we found that SUF4 directly interacts with EBS in vivo and in vitro. Loss of function of SUF4 and/or EBS resulted in disorganization of the QC, aberrant cell division, and stunted root growth. RNA-seq and reverse transcription quantitative real-time polymerase chain reaction analysis revealed that SUF4 and EBS coregulate many root development-related genes. A series of biochemical analyses demonstrated that SUF4 directly binds to the promoter of SCARECROW (SCR), which encodes a key regulator of root development. Chromatin immunoprecipitation assay indicated that both SUF4 and EBS are recruited to the SCR locus in an interdependent manner to promote H3K4me3 levels and suppress H3K27me3 levels, thereby activating the expression of SCR. These findings improve our understanding of the function of SUF4 and EBS and provide insights into the molecular mechanism that couples a transcription factor and a histone methylation reader to modulate QC specification and root development in Arabidopsis.

Effects of screen exposure on morbidity risk in children with autism spectrum disorder and language retardation / 中华行为医学与脑科学杂志

Objective:To explore the effects of screen exposure on morbidity risk in children with autism spectrum disorder (ASD) or language retardation.Methods:In a case-control study, 64 children with autism spectrum disorder were selected as the ASD group, 64 children with language retardation as the language retardation group, and 52 normal children as the control group. Descriptive analysis, t-test, Chi-square test, Logistic regression analysis and other statistical methods of SPSS 17.0 software were used to analyze the data.The differences of screen exposure between the case groups and control group were compared to analyze the effects of screen exposure on the diseases. Results:There were statistically significant differences in daily cumulative screen time ( F=27.758), duration of screen exposure ( F=12.516), first-time exposure to screen(χ 2 = 13.749) and parents' explanation during screen contact(χ 2 = 16.368) among the three group (all P<0.05). The proportion of first-time exposure to screen before 1 year old was 65.62% (42/64) in ASD group, 40.63% (26/64) in language retardation group and 33.33%(17/51) in control group. Compared with the control group ((1.42±1.44)h), the ASD group ((4.04±2.00)h) and the language delay group ((3.53±2.07)h) had longer daily cumulative screen time, and the differences were statistically significant (both P<0.05). Compared with the control group ((6.14±4.59) months), children in the ASD group ((11.97±7.32) months) or the language retardation group ((9.96±5.15) months) had the longer duration of screen exposure, and the differences were statistically significant (both P<0.05). Compared with the control group, parents in ASD group and language retardation group elaborated less while the children were exposed to screen, the differences were statistically significant (both P<0.05). Logistic regression analysis showed that cumulative daily exposure time less than 2 hours ( β=-5.338, OR=0.005, 95% CI=0.001-0.120), democratically parenting style ( β=-3.279, OR=0.038, 95% CI=0.003-0.554), paternal age less than 35 years old ( β=-5.432, OR=0.004, 95% CI=0.001-0.691) were protective factors for autism spectrum disorder, while paternal education level below junior college was a risk factor ( β=3.125, OR=22.755, 95% CI=1.866-277.463). Cumulative exposure time less than 2 hours per day ( β=-3.357, OR=0.035, 95% CI=0.002-0.526) was a protective factor for language retardation, and paternal education less than college degree ( β=2.740, OR=15.482, 95% CI=1.350-177.573) was a risk factor for language retardation. Conclusion:Excessive screen exposure has certain effects on morbidity risk of autism spectrum disorder and language retardation, which should be paid more attention to.

[The role of serum hepcidin and ferroportin1 in placenta on iron transfer from mother to fetus].

OBJECTIVE: To detect the concentration of serum hepcidin and the mRNA expression level of ferroportin1 (FPN1) in the placenta membrane from full term pregnant women with different degree of iron deficiency, and explore their roles for iron transport in placental. METHODS: The concentration of HGB, serum iron (SI) and serum ferritin (SF) of mothers and infants were detected in 55 full term pregnant women and neonates. The expression level of FPN1 mRNA in placental was detected by the RT-PCR technique. The concentration of serum hepcidin was detected by double antibody sandwich biotin avidin enzyme-linked immunosorbent assay. The serum hepcidin level and the FPN1 mRNA expression in the full term placenta from different maternal iron status were compared in three groups. RESULTS: There were no significant differences in the cord blood HGB, SI and SF of newborns from pregnant women with different iron status (P>0.05). The concentration of serum hepcidin of pregnant women among normal, iron deficiency and mild iron deficiency anemia were (193.637±52.219), (176.523±43.875), and (147.623±37.768) µg/L respectively, with statistical significance (F=3.872, P=0.027). The expression levels of FPN1 mRNA among three groups were 0.462±0.077, 0.507±0.074 and 0.551±0.104 respectively, with statistical significance (F=4.767, P=0.013). A negative correlation between maternal serum hepcidin and placental FPN1 mRNA (r=-0.383, P=0.004) was identified. CONCLUSION: There were no significant differences in the iron status of corresponding newborns from pregnant women with different iron status. With the severity of maternal iron deficiency, the concentration of serum hepcidin was down-regulated, while the expression of FPN1 mRNA in placenta was up-regulated.

[Preliminary study on human mature placenta tissue-derived hematopoietic stem/progenitor cells].

Clinical transplantation has indicated that cord blood (CB) can be used in the hematopoietic reconstitution in the children, but not well used in the adult patients because of the low cell amount. The present study aimed to explore the capability of proliferation and differentiation of the hematopoietic stem/progenitor cells derived from human mature placenta tissue (PT) in vitro, and to find a new source of hematopoietic/progenitor cells for clinical transplantation. CD34(+) cells in human mature placenta tissue were isolated and characterized by using enzyme-digestion method and flow cytometry. A long culture system without cytokines was established with human mature placenta tissue-derived mononucleated cells and cord blood mononuclear cells. The number of nucleated cells was weekly counted in culture for 14 weeks. The number of CFC was counted in culture for 2 weeks. The results showed that the CFC yields (CFU-GM, 186.90 +/- 24.52; BFU-E, 101.40 +/- 13.35) and the percentage of CD34(+) cells (2.74 +/- 0.61%) and CD34(+)/CD38(-) cells (2.46 +/- 0.42%) in placenta tissue (PT) were higher than CFC (CFU-GM, 136.90 +/- 25.15; BFU-E, 49.20 +/- 8.13), CD34(+) cells (1.73 +/- 0.32%) and CD34(+)/CD38(-) cells (0.80 +/- 0.25%) in cord blood (CB). The MNCs from PT have shown more survival ability than the cells from CB in the long-term cell culture condition; and the cells from PT increased by 2 times. It is concluded that the placenta may be another hematopoietic organ in ontogeny. The cells from placenta were more juvenile, and may be favorable source for clinical stem cell transplantation.