Background: The liver-specific microRNA-122 (miR-122) has been demonstrated as a powerful and promising biomarker of hepatic diseases. However, the researches on the accuracy of miR122 detection in chronic viral hepatitis have been inconsistent, leading us to conduct this meta-analysis to systematically summarize the diagnostic value of circulating miR-122 in patients with hepatitis B virus (HBV) and/or hepatitis C virus (HCV)-associated chronic viral hepatitis. Methods: A comprehensive literature search (updated to January 30, 2019) in PubMed, Cochrane library, EMBASE, CNKI, Wanfang, and CQVIP databases was performed to identify eligible studies. The sensitivity (SEN), specificity (SPE), positive and negative likelihood ratios (PLR and NLR), diagnostic odds ratio (DOR), and area under the curve (AUC) were pooled to explore the diagnostic performance of circulating miR-122. Subgroup and threshold effect analysis were further carried out to explore the heterogeneity. Results: Overall, 15 studies were finally included in this meta-analysis according to the exclusion and inclusion criteria. The pooled estimates indicated a moderately high diagnostic accuracy for circulating miR-122, with a sensitivity of 0.92 [95% confidence interval (CI), 0.86–0.95], a specificity of 0.84 (95% CI, 0.78–0.89), a PLR of 5.7 (95% CI, 4.7–8.1), a NLR of 0.1 (95% CI, 0.06–0.18), a DOR of 57 (95% CI 25-129), and an AUC of 0.93 (95% CI, 0.91–0.95). The subgroup analysis demonstrated that diagnostic accuracy was better for HCV-associated chronic viral hepatitis patients and non-Chinese compared with other subgroups. In addition, we found that serum might be a more promising matrix for detecting the expression of miR-122 than plasma. Conclusions: Our results demonstrated that circulating miR-122 have a relatively high diagnostic value for chronic viral hepatitis detection, especially in the patients with HCV-associated chronic viral hepatitis. However, further large cohort studies are still required to confirm our findings.
RDR6 (RNA-dependent RNA polymerase 6) is not only involved in virus resistance but also plays an important role in natural plant development. In the present study, a novel RDR gene, named GhRDR6 ( Gossypium hirsutum RDR6 ), was isolated from cotton ( G. hirsutum L.). Alignment and evolutionary relationship analyses showed that GhRDR6 was more closely related to RDR6 than to other RDRs. Expression analysis indicated that this single-copy gene is constitutively expressed in the roots, stems and leaves. Semi-quantitative RT–PCR (reverse transcription–PCR) showed that GhRDR6 was up-regulated by the application of various phytohormones, including MeJA [methyl JA (jasmonate)], ABA (abscisic acid), JA, α-naphthylacetic acid, gibberellins and ET (ethylene). In addition, GhRDR6 expression increased in response to wounding, cold (4°C) and NaCl treatments, but not by drought. Furthermore, overexpression of GhRDR6 in transgenic Nicotiana benthamiana plants resulted in root lengths longer than the wide-type during the seeding stage. Interestingly, the GhRDR6-overexpressing plants displayed reduced tolerance to oxidative damage, resulting in reduced ABA-sensitivity, but they tolerated freezing. Moreover, resistance to potato virus Y was enhanced in transgenic N. benthamiana plants. These results suggest that GhRDR6 may play an important role in plant defence responses and a pivotal role in plant development.