RNA甲基化修饰m~6A在动物中的研究进展

DNA、RNA和蛋白质的化学修饰都是表观遗传学重要的研究内容,近年来,随着科学技术的快速发展,基于DNA和蛋白质修饰研究基础,RNA甲基化研究在表观遗传领域已成为前沿的研究热点。在150余种RNA化学修饰中,RNA甲基化修饰约占60%以上,广泛分布于各种类型的RNA中,各种甲基化修饰在细胞内行使着不同的生物学功能,其中RNA甲基化修饰m~6A是最常见、最丰富的真核生物mRNA转录后修饰。m~6A的形成过程是由甲基转移酶复合体(METTL3、METTL14和WTAP等组成)、去甲基酶(FTO和ALKBH5)以及结合蛋白(YTHDF1/2/3、YTHDC1)动态调控,与基因表达调控密切相关。其次,m~6A可能参与了mRNA转录、选择性剪切、出核转运、翻译及降解等过程,从而导致RNA功能紊乱,进而影响一系列的动物生命活动。因此RNA甲基化修饰m~6A介导的表观遗传学调控对动物繁殖以及生长发育有着重要的意义。本文重点根据在动物方面相关研究对m~6A的动态调控及由调控过程所产生的影响进行归纳总结。     

mRNA中N~6-甲基腺苷修饰及其在动物中的研究进展

N~6-甲基腺苷(m~6A)修饰是动物RNA修饰中最丰富的一种,其受甲基转移酶、脱甲基酶和m~6A结合蛋白的动态调控。mRNA中m~6A修饰可以调节大多数RNA代谢过程以及在动物体内发挥重要的生理作用。本文主要介绍了动物mRNA中m~6A修饰的分布与表达、检测方法、甲基化代谢相关酶及其生理功能的研究进展,并对目前m~6A修饰研究中存在的问题或挑战进行展望,为进一步研究m~6A修饰提供参考。     

RNA m~6A甲基化修饰及其在家禽中的研究进展

N6-甲基腺嘌呤(m~6A)是真核生物mRNA上含量最丰富的一种RNA修饰。近年来,随着m~6A甲基化修饰研究技术的不断发展,m~6A甲基化修饰调控的生物学功能得到了更深入的研究。文章综述了m~6A甲基化修饰的特点、调控机制、生物学功能及其在家禽中的研究进展,以期为进一步解析m~6A甲基化修饰在家禽生长发育、繁殖等方面的作用提供理论依据。     

N~6-甲基腺嘌呤RNA修饰研究进展

N~6-甲基腺嘌呤(N~6-methyladenosine,m6A)作为一种重要的表观遗传修饰方式,在干细胞命运决定、精子形成、肌肉发育、脂肪沉积及人类肿瘤发生中发挥重要作用。m~6A修饰最重要的作用是调控基因表达,它是细胞中基因表达调控的表观遗传学机制之一。文章综述了m~6A调控基因表达的分子机制及m~6A介导的生物学功能的研究进展,探讨了m~6A RNA甲基化的研究趋势和未来发展方向。     

m6A修饰及其生殖调控功能研究进展

N6-甲基腺苷(N6-methyladenosine,m6A)修饰是指mRNA中腺苷酸(A)的第六位氮原子处发生甲基化,m6A修饰是生物mRNA中最广泛存在的内部修饰.m6A修饰通过调节RNA代谢、稳定性、翻译、降解以及选择性剪接来发挥生物学功能,在细胞分化、生物节律、生殖生理、肿瘤发生等方面起到调控作用.本文综述了目...     

RNA N6-腺苷酸甲基化修饰及其生物学功能

N⁶-腺苷酸甲基化(N⁶-methyladenosine,m⁶A)是真核生物mRNA的一种转录后修饰,是一个动态可逆过程,由甲基转移酶、去甲基化酶和结合蛋白催化,介导真核生物的各种生物学过程,参与多种细胞基因表达调控和疾病的病理过程。近年来,随着人们对RNA修饰认识的不断深入和和高通量测序技术的发展,人们对m⁶A甲基化修饰在细胞分化、动物生长发育、疾病的发生等生物学功能的探索也越来越迫切。作者介绍了m⁶A甲基化修饰的特征及其相关的3种酶、m⁶A修饰的检测技术,及其在mRNA调控、干细胞分化、肿瘤发生和转移上的生物学功能,简述了m⁶A甲基化修饰对畜禽(如猪、鸡)生长发育方面的调控,最后对m⁶A甲基化修饰在未来的研究方向及发展前景做出展望,以期为后续m⁶A甲基化修饰在动物生长过程中的深入研究和预防治疗疾病上的应用提供参考。     

家禽m6A修饰研究进展

N6-甲基腺嘌呤(m6A)作为一种重要的RNA表观遗传修饰方式,在真核生物基因组中广泛分布,已被证实在细胞分化、配子发生、脂肪沉积及肿瘤发生等生命过程中发挥重要作用。随着高通量检测技术和单碱基检测技术的快速发展,大量的m6A修饰调控蛋白被鉴定出来,相应的调控机理也得到了更深入的解析。文章综述了m6A的发现和特征、调控酶系统、检测技术、主要生物学功能及在家禽方面的研究进展,以期为后续对家禽m6A修饰的研究及应用提供理论支撑。     

水生所揭示精氨酸甲基转移酶prmt5在斑马鱼性腺发育中的功能和机制

<正>蛋白质精氨酸甲基化是一类重要的蛋白质翻译后修饰型式,它受精氨酸甲基化转移酶基因家族的介导,在RNA加工、DNA修复、蛋白与蛋白相互作用及基因调控等方面起非常重要的作用。精氨酸甲基转移酶prmt5为该基因家族成员之一,属Ⅱ型精氨酸甲基化转移酶,介导对称性     

RNA甲基化调控猪肉品质的研究进展

随着生活水平的提高，消费者对猪肉品质要求越来越高，如何提升猪肉品质是畜牧业生产中面临的重大课题。RNA甲基化修饰是真核生物中最丰富的一种表观遗传修饰，在多种生命过程中发挥重要的调控作用。越来越多的研究发现，脂肪沉积与猪肉品质密切相关，RNA甲基化对猪脂肪沉积具有一定的调控作用。因此，本文在概述了猪肉品质的影响因素和RNA甲基化生物学功能的基础上，阐述了RNA甲基化介导的转录后修饰对猪脂肪沉积的影响及调控机制等方面的研究进展，以期为调控猪肉品质、促进我国畜牧业高质量发展提供新思路。     

DNA甲基化与去甲基化调控肌肉发育研究进展

肌肉发育是一个复杂的生物学过程,其调控机制尚不完善。但近年来表观遗传修饰对肌肉发育的调控作用逐渐成为热点领域,研究发现DNA甲基化与去甲基化修饰对肌肉发生与发育起到重要的调控作用。肌肉干细胞特异位点通过DNA甲基化修饰,影响肌肉发育过程关键基因的表达,进而调控早期发育的生肌过程。本文主要围绕肌肉发育过程中DNA甲基化及去甲基化修饰的变化、重要的甲基转移酶和去甲基化酶以及营养物质通过DNA甲基化修饰影响肌肉发生的作用进行论述。     

Aberrant regulation of RNA methylation during spermatogenesis

Natural modifications of cellular RNA include various chemical modifications, such as N6-methyladenosine (m⁶A), which enable the orderly metabolism and function of RNA structural diversity, thereby affecting gene expression. Spermatogenesis is a complex differentiating developmental process, which includes the proliferation of spermatogonial stem cells, spermatocyte meiosis and sperm maturation. Emerging evidence has shown that RNA methylation can influence RNA splicing, exportation and translation, which are controlled in the male germline in order to ensure coordinated gene expression. In this review, we summarize the typical characteristics of different types of RNA methylation during the process of spermatogenesis. In particular, we emphasize the functions of the RNA methylation effectors during the male germ cell development.     

抗菌肽[L6,K11]-IsCT抑菌性能及其稳定性研究

IsCT最初是从蝎子中分离出的一种非细胞选择性线性抗菌肽,为了将其应用于动物饲料,需研究其对常见致病菌的抑制和杀灭作用。本试验采用微量稀释法和琼脂扩散法对ISCT衍生物[L⁶,K¹¹]-IsCT的抗菌活性及其稳定性进行探索。结果显示,相对于金黄色葡萄球菌,[L⁶,K¹¹]-IsCT对大肠杆菌具有更好的抑制作用,其对大肠杆菌的最小抑菌浓度为50 μg/mL。另外,该衍生物对高温表现出很好的稳定性,同时具有很好的酸碱耐受性和人工胃液耐受性。经121 ℃、0.12 MPa处理30 min,以及2.0≤pH≤11.0处理30 min或人工胃液2 h孵育处理后,依然能保持很好的抑菌活性。     

The γδ cells as marker of non-seroconverted cattle naturally infected with Mycobacterium avium subspecies paratuberculosis

Early diagnosis of MAP infection is a pressing need to enable efficient intervention with the spread of MAP infection in herds. Hence, study of lymphocyte subsets and their expressed adhesion molecules could contribute in defining a distinct diagnostic marker (or markers) at the subclinical period of the infection that could in turn facilitate the development of effective diagnostic approach. In accordance with this objective, milk and blood samples were collected from two groups of cattle naturally infected with MAP and their corresponding negative controls. Group (C) comprised 3-4 year-old ELISA negative/PCR positive-cattle that were considered as subclinical seronegative low shedder group (early stage). Group (A) included 6-8 year-old ELISA positive-cattle, which were considered as a clinical seropositive group (late stage). Flow cytometry of B cells, CD8⁺, CD4⁺ and γδ cells and the adhesion molecules CD44⁺, CD62L, LFA-1 and LPAM-1 indicated increase in CD4⁺ and B cells levels, with higher levels in blood than milk of group A, and significant expression of CD44⁺ in blood and milk and LPAM-1 in blood only. The CD8⁺ cells count in milk was higher than blood in the late stage. The peculiar feature of the early stage (group C) was the high level of γδ cells in the blood and milk, with tendency to express high level of CD62L. Compelling evidence could support the assumption that the dominant γδ cells at early stage of MAP infection could be of CD8CD2⁻WC+1⁺ phenotype. γδ cells appear as promising markers in defining early changes of MAP infection due to their important role in priming innate and cell mediated immunity. Possible utilization of these peculiar changes in the γδ cells level in the early diagnosis of MAP infection should be the subject of further research.     

The effect of medetomidine on the regional cerebral blood flow in dogs measured using Technetium-99m-Ethyl Cysteinate Dimer SPECT

Sedatives and anaesthetics are known to cause changes in the regional cerebral blood flow. In dogs intramuscular sedation with medetomidine, a potent sedative frequently used in veterinary medicine, is sometimes indicated prior to intravenous injection of ^99mTechnetium-Ethyl Cysteinate Dimer (^99mTc-ECD) in brain perfusion studies using Single Photon Emission Computed Tomography (SPECT). Based on the knowledge of the distribution of alpha₂-receptors in the brain, we hypothesized altered regional brain perfusion in dogs receiving medetomidine prior to ^99mTc-ECD. Two conditions were compared in 10 dogs; tracer injection before and after intramuscular sedation with medetomidine. In our study, medetomidine caused a significantly higher tracer uptake in all brain regions. Semi-quantification of brain perfusion rendered a lower perfusion index in the subcortical region and an imbalance between left and right cortical perfusion induced by medetomidine. This study shows that caution is needed when quantifying the brain perfusion indices under medetomidine sedation.     

Factors affecting disease manifestation of toxocarosis in humans: Genetics and environment

Toxocara canis is regarded as the main cause of human toxocarosis but the relative contribution of T. cati is probably underestimated; serological and other diagnostic methods used in most studies of this zoonotic disease do not distinguish between the two parasites. The definitive hosts for T. canis are caniidae. Pups generally have higher infection rates than adult animals and are a major source of eggs in the environment. Humans usually acquire T. canis infection by accidental ingestion of embryonated eggs or encapsulated larvae from the environment or contaminated food, such infections may lead to visceral larva migrans (VLM), ocular larva migrans (OLM) or covert toxocarosis (CT). Although a mixed Th1- and Th2-mediated immunological response, particularly with high levels of IgE and eosinophilia is observed, the underlying mechanisms of molecular and immunopathogenesis for the development of the symptomatic syndromes of VLM, OLM, or of asymptomatic CT are largely unclear. Studies have indicated that immunological defences against various infectious diseases may be highly influenced by complex interactions of environmental and host genetic factors e.g. MHC class I and II, also known as human leucocyte antigen (HLA). Toxocara spp. infections are associated with a polarized CD4⁺ Th2 response with high IgE levels and eosinophilia, mediated mainly by HLA class II molecules. Associations have been made between HLA class II and pathological severity and host genetic effects on exposure to infection. Recent research suggests Foxp3⁺ CD4⁺CD25⁺-expressing T regulatory (Treg) cells play a role in regulation of the immunopathology of granulomas in experimental toxocaral granulomatous hepatitis and in enhanced expression of TGF-β1, which is an important factor for the local survival and function of Treg observed during T. canis invasion in the mouse small intestine, liver, muscle, and brain. Since the potential susceptibility loci HLA class II molecules, are considered involved in the regulation of a Th2-dominant immunity which is highly controlled by Foxp3⁺ CD4⁺CD25⁺ Treg cells by stimulation through TGF-β1, which thus provides a beneficial environment to T. canis larvae but severe injuries to local organs. However, TGF-β1 variant Leu10Pro known to be involved in disease severity warrants further elucidation as this too may have a role in the severity of human toxocarosis. Exploration of TGF-β1 polymorphism, Foxp3⁺ CD4⁺CD25⁺ Treg cells, and MHC polymorphisms may allow insight into the contribution made by environmental and genetic factors in influencing disease syndrome type and severity in humans with toxocarosis.     

Phosphorylation of histone H3 on Ser10 by auto-phosphorylated PAK1 is not essential for chromatin condensation and meiotic progression in porcine oocytes

Background

The p21-activated kinase 1 (PAK1) is essential for mitosis and plays an important role in the regulation of microtubule assembly during oocyte meiotic maturation in mice; however, little is known about its role in porcine oocytes.

Result

Total p21-activated kinase 1 (PAK1) and phosphorylated PAK1 at Thr423 (PAK1^Thr423) were consistently expressed in porcine oocytes from the germinal vesicle (GV) to the second metaphase (MII) stages, but phosphorylation of histone H3 at Ser10 (H3^Ser10) was only expressed after the GV stage. Immunofluorescence analysis revealed that PAK1^Thr423 and H3^Ser10 colocalized on chromosomes after the GV stage. Blocking of endogenous PAK1^Thr423 by injecting a specific antibody decreased the phosphorylation level of H3^Ser10; however, it had no impact on chromatin condensation, meiotic progression, cleavage rate of blastomeres or the rate of blastocyst formation.

Conclusion

Phosphorylation of PAK1^Thr423 is a spontaneous activation process and the activated PAK1^Thr423 can promote the phosphorylation of H3^Ser10; however, this pathway is not required for meiotic maturation of porcine oocytes or early embryonic development.     

The distribution of 35S-sulfadiazine and 14C-trimethoprim in rainbow trout, Salmo gairdneri.

The distribution of ³⁵S-labelled sulfadiazine and ¹⁴G-labelled trimethoprim was studied in rainbow trout by use of whole body autoradiography and liquid scintillation. As compared to mammals, gastrointestinal absorption and elimination were slow. Accumulation in the skin and the uveal tract of the eye was observed for both drugs tested. The results also indicated that the bile was an important route of excretion. Considerable radioactivity was still present in the skin at 144 hr. survival time.     

Effect of Cadmium in Feed on Organs and Meat Colour of Growing Pigs

One hundred and ninety-two barrows (Duroc × Landrace × Yorkshire, initial weight 27.7 kg) were used to investigate the effects of cadmium in feed on the function of selected organs and meat colour of growing pigs. The pigs were randomly allocatted into four different treatments. Each treatment included three replications with 16 pigs per replicate. The animals were fed corn–soybean basal diet and supplemented with 0, 0.5, 5.0, 10.0 mg/kg cadmium (as CdCl₂), respectively. The feeding trial ended when the average body weight of the pigs reach 90 kg. The results showed that, compared with controls, addition of 10 mg/kg cadmium to the diet resulted in significant elevations of relative weight of liver and spleen by 18.3% (p < 0.05) and 19.7% (p < 0.05) respectively, and of serum glutamic-pyruvic transaminase (GPT) and glutamic-oxaloacetic transaminase (GOT) activities by 17.8% (p < 0.05) and 27.4% (p < 0.05) respectively; and significant decreases of Na⁺/K⁺-ATPase activity in the liver by 24.6% (p < 0.05), the redness of longissimus dorsi by 26.6% (p < 0.05) and 24.9% (p < 0.05) at 0.75 h and 16 h post mortem, respectively, and of the myoglobin content of longissimus dorsi by 19.4% (p < 0.05). No changes were found in these indices above when the pigs were fed the diet supplied with 0.5 or 5 mg/kg cadmium (p > 0.05), nor in renal functions among cadmium-treatment treatments (p > 0.05) as indicated is the activities of urinary N-acetyl-β-d-glucosaminidase (NAG) and alkaline phosphatase (ALP) and the content of urinary protein. The study indicated the adverse effects of 10 mg/kg cadmium in feed on liver functions and meat colour of growing pigs.     

Renal excretion of N4-acetyl sulphanilamide and N4-acetyl sulphadimidine in goats

The renal excretion of N⁴-acetyl sulphanilamide and N⁴-acetyl sulphadimidine was studied in 19 experiments with 6 goats during continuous intravenous administration of the 2 sulphonamide derivatives. Deacetylation of both compounds takes place to a small extent only. Further it is shown that both sulphonamide derivatives are bound to plasma proteins to a greater extent than sulphanilamide and sulphadimidine. The excretion of the N⁴-acetylated sulphonamides is compared with the renal excretion of creatinine. The non-protein-bound fraction of the 2 N⁴-acetylated sulphonamides is excreted by filtration and active tubular secretion. The renal clearances of the acetyl derivatives are higher than those of the parent compounds.     

Hepatic expression of FTO and fatty acid metabolic genes changes in response to lipopolysaccharide with alterations in m6A modification of relevant mRNAs in the chicken

1. The fat mass and obesity associated (FTO) gene, which encodes a demethylase of m⁶A, has been reported to respond to lipopolysaccharide (LPS) and to serve as a link between inflammation and metabolic responses. The objective of this study was to determine whether LPS-induced changes in the expression of FTO and metabolic genes are associated with alterations of m⁶A in relevant mRNAs.

2. LPS challenge significantly decreased hepatic mRNA expression of carnitine palmitoyl transferase 1 (CPT1) and CPT2, which coincided with a tendency of higher triglyceride accumulation in the liver.

3. LPS significantly down-regulated the full length cFTO1, yet up-regulated the truncated cFTO4 protein in the liver nuclear extracts.

4. Nuclear protein content of cFTO4 in the liver was negatively correlated with the mRNA abundances of CPT1 (r = 0.629) and CPT2 (r = 0.622).

5. Methylated RNA immunoprecipitation analysis revealed that the m⁶A level around the translation start site of CPT1 was markably decreased in the liver of LPS-treated chickens.

6. These results indicate that LPS-induced changes in FTO protein expression are associated with alteration of mRNA m⁶A modification in chicken liver.