DDX21 mediates co-transcriptional RNA m6A modification to promote transcription termination and genome stability

N6-methyladenosine (m6A) is a crucial RNA modification that regulates diverse biological processes in human cells, but its co-transcriptional deposition and functions remain poorly understood. Here, we identified the RNA helicase DDX21 with a previously unrecognized role in directing m6A modification on nascent RNA for co-transcriptional regulation. DDX21 interacts with METTL3 for co-recruitment to chromatin through its recognition of R-loops, which can be formed co-transcriptionally as nascent transcripts hybridize onto the template DNA strand. Moreover, DDX21's helicase activity is needed for METTL3-mediated m6A deposition onto nascent RNA following recruitment. At transcription termination regions, this nexus of actions promotes XRN2-mediated termination of RNAPII transcription. Disruption of any of these steps, including the loss of DDX21, METTL3, or their enzymatic activities, leads to defective termination that can induce DNA damage. Therefore, we propose that the R-loop-DDX21-METTL3 nexus forges the missing link for co-transcriptional modification of m6A, coordinating transcription termination and genome stability.

ssc-miR-204 regulates porcine preadipocyte differentiation and apoptosis by targeting TGFBR1 and TGFBR2

MicroRNAs (miRNAs) take part in a variety of biological processes by regulating target genes. Transforming growth factor β receptor 1 (TGFBR1) and TGFBR2 are crucial members of the TGF-β family and are serine/threonine kinase receptors. The aim of this study was to explore the functions of ssc-miR-204 in porcine preadipocyte differentiation and apoptosis with regard to the TGFβ/Smad pathway. We identified miRNAs predicted to target TGFBR1 and TGFBR2 using a database and selected ssc-miR-204 as a candidate miRNA. ssc-miR-204 overexpression dramatically reduced the levels of TGFBR1 and TGFBR2. However, after transfection with ssc-miR-204 inhibitor, TGFBR1 and TGFBR2 levels were dramatically increased. ssc-miR-204 overexpression dramatically promoted porcine preadipocyte differentiation and apoptosis. After transfection with ssc-miR-204 inhibitor, porcine preadipocyte differentiation and apoptosis were dramatically inhibited. After transfection with ssc-miR-204 mimics, Smad2, Smad3, Smad4, p-Smad2, and p-Smad3 protein levels significantly decreased, and adipogenesis was regulated by inhibiting the TGF-β/Smad3 signaling pathway. Taken together, these results verified that ssc-miR-204 regulates porcine preadipocyte differentiation and apoptosis by targeting TGFBR1 and TGFBR2.

[Effects of different frequencies of electroacupuncture on blood glucose level in impaired glucose tolerance patients]

OBJECTIVE

To Investigate the clinical efficacy of electroacupuncture (EA) at different frequencies for patients with impaired glucose tolerance (IGT).

METHODS

A total of 120 IGT outpatients were randomly divided into control, EA-5 Hz, EA-50 Hz, and EA-100 Hz groups (n = 30/group). EA (1 mA) was applied to bilateral Pishu (BL 20), Shenshu (BL23), Zusanli (ST 36) and Sanyinjiao (SP6) for 20 min, once daily for 60 sessions. Body mass index (BMI), fasting blood glucose (FBG) and 2-hour post-prandial blood glucose (2 h PBG) contents were detected by using BAYER Blood Sugar Analyzer and glycosylated haemoglobin (HbA1c) content was detected by enzymatic assay.

RESULTS

Following the treatment, both HbA1c and 2 h PBG levels in the EA-5 Hz group were significantly lower than those of the control group and those of pre-treatment in the same one group (P < 0.05, P < 0.01). No significant differences were found between the EA-5 Hz and control groups, between pre-treatment and post-treatment in the EA-5 Hz group in BMI and FBG levels; between the EA-50 Hz and control groups, between the EA-100 Hz and control groups, and between pre-treatment and post-treatment in the EA-50 Hz and EA-100 Hz groups in BMI, FBG,2 h PBG and HbA1c levels (P > 0.05).

CONCLUSION

Lower frequency EA of BL 20, BL 23, ST 36 and SP 9 can reduce HbA1c and 2 h PBG levels in IGT patients, suggesting a helpful effect of EA in controlling the development of diabetes.

[Clinical observation on acupuncture for treatment of reflux esophagitis of heat stagnation of liver and stomach type]

OBJECTIVE

To observe the clinical therapeutic effect of acupuncture for treatment of reflux esophagitis of heat stagnation of liver and stomach type.

METHODS

Sixty-one cases were randomly divided into an acupuncture group (31 cases) and a medication group (30 cases). The acupuncture group was treated with needles at Zusanli (ST 36), Zhongwan (CV 12), Weishu (BL 21) and Neiguan (PC 6) mainly, once a day; and the medication group was treated with oral administration of 20 mg Omeprazole, once a day. The scores of clincial symptoms, comprehensive therapeutic effect, results of gastroscopy and pathology as well as recurrence rate etc. were observed before and after treatment.

RESULTS

After treatment, the scores of symptoms significantly decreased in the two groups (both P < 0.01). The total effective rate of the acupuncture group was 90.3% (28/31), and 90.0% (27/30 )in the medication group, there was no statistical difference between two groups (P > 0.05); results of gastroscopy and esophageal mucosa pathology showed no statistical difference between two groups (both P > 0.05), the recurrence rate 12 weeks after treatment of 9.1% in the acupuncture group was lower than that of 42.9% in the medication grou p (P < 0.05).

CONCLUSION

Acupuncture has preferable short and long-term therapeutic effects for treatment of reflux esophagitis of heat stagnation of liver and stomach type.

Synergistic effect in treatment of C.I. Acid Red 2 by electrocoagulation and electrooxidation

An aqueous C.I. Acid Red 2 solution was decolorized by electrolysis using iron as anode. The decolorization mechanism was investigated through experimental observations on the electrochemical behavior of C.I. Acid Red 2 on Pt rotating disk electrode, UV-visible spectra of the solution and IR spectra of the coagulated mixtures. It is found that the decolorization efficiency is high, over 98.0% after 40 min, and this high decolorization efficiency can be ascribed to the synergistic effect of electrocoagulation and electrooxidation. The electrocoagulation results from the electrogenerated iron hydroxide and the electrooxidation results from electrogenerated ferric ions. The results obtained from IR spectra shows that the decolorization of C.I. Acid Red 2 by electrooxidation is due to the partial or complete cleavage of C-N bonds in C.I. Acid Red 2.

[Research on the name and reality of zishen in ancient and modern]

The variety of Zishen was confused in the past records. Its original plant should be Polygonum bistorta. The crude drugs bearing the name of Zishen are varied presently. Their functions are completely different from what is recorded in "Benjing". Thus it is suggested that the name Zishen be discarded and replaced by "Quanshen".

[Continuity and changes of medical varieties of rhizoma Corydalis in modern and ancient times]

Through systematic textual research on Bencao, it is definite that the initial medical variety of Rhizoma Corydalis was Corydalis tartschaninovii produced in the northeast of China. After the Ming Dynasty, it was replaced gradually by the cultivated variety in Jiangsu Province and Zhejiang Province. At present, Corydalis turtschaninovii should be the variety of first choice among the medical resources of Rhizoma Corydalis.