Correction to: ZNF143 is a regulator of chromatin loop.

There are some errors in Fig. 1. First, owing to a production error, the sub-figure labels a, b, and c were absent in the online version, and the proportion number 55.1% together with its bracket for cell type HelaS3 were messy in Fig. 1a.

ZNF143 is a regulator of chromatin loop.

It is known that transcription factor ZNF143 frequently co-binds with CTCF-Cohesin complex in the anchor regions of chromatin loops. However, there is currently no genome-wide experiment to explore the functional roles of ZNF143 in chromatin loops. In this work, we used both computational and experimental analyses to investigate the regulatory effect of ZNF143 on chromatin loops. By jointly analyzing the ZNF143 and CTCF motifs underlying the isolated ZNF143-binding sites, ZNF143-CTCF co-binding sites and ZNF143-CTCF-RAD21 co-binding sites, our result shows that the ZNF143-CTCF-RAD21 co-binding sites are enriched with CTCF motifs but depleted of Znf143 motifs, implying that the CTCF but not ZNF143 may directly binds to the genome and thus ZNF143 may act as a cofactor instead of pioneer factor of ZNF143-CTCF-Cohesin complex. To explore the regulatory effect of ZNF143 on chromatin loops, we conducted siRNA experiment to knock down the expression level of ZNF143 in HEK293T cell line, and then performed in situ Hi-C on the negative control and ZNF143-silenced HEK293T cells. Comparison shows that the majority of chromatin loops are lost or at least weakened in the ZNF143-silenced HEK293T cells. However, a small proportion of chromatin loops are gained or strengthened, indicating the complicated roles of ZNF143 reduction in regulating chromatin loops. To further validate the loop analyses, we thoroughly investigated the chromatin loop changes between negative control and ZNF143-silenced cells by using aggregate peak analysis. The calculation shows that the lost and gained chromatin loops do undergo loop strength changes after ZNF143 silencing. Altogether, our work shows that ZNF143 can regulate chromatin loops by acting as a cofactor of CTCF-Cohesin complex, and knocking down ZNF143 expression level mainly eliminates or destabilizes chromatin loops.

[Determination of trace mercury species in water and soil samples with atomic fluorescence spectrometry].

With hydride generation-cold atomic fluorescence spectrometry (HG-AFS), the method of determining trace mercury species in water and soil samples in Jimei, Xiamen city, China was established. The content of inorganic mercury in water was measured by sample direct injection, while the total mercury was measured after digestion with the reagents of KBrO3-KBr. The soil samples were digested with microwave for total mercury measurement. Sequential extraction procedure was carried out for determining different mercuric species in soil samples. The results indicated that the mercury concentration of wastewater from chemical laboratory exceeded the limit of the integrated wastewater discharge standard of China (GB 8978-1996). It is one of the serious pollution sources of mercury in environment. The mercury contents from soil samples including the sideward soil of highway, the sea sediment and the garden soil were under the limits of relative national standards of China. However, attention should be paid to the accumulation of mercury in garden soil due to the artificial pollution. Meanwhile, the average recoveries for water and soil samples tested with adding standards were 93.7% and 93.8%, respectively. Meanwhile, the detection limits estimated with 3-fold standard deviation were 0.000 8 microg x L(-1) for water and 0.072 3 microg x kg(-1) for soil, respectively. The results indicated that the established method, with the merits of high sensitivity and precision, was suitable for the measurement of trace mercury species in environmental samples.