Identification and validation of housekeeping genes as internal control for gene expression in an intravenous LPS inflammation model in chickens

Real-time PCR has become a powerful tool for the detection of inflammatory parameters, including cytokines. Reference or housekeeping genes are used for the normalization of real-time RT-PCR results. In order to obtain reliable results, the stability of these housekeeping genes needs to be determined. In this study the stability of five genes, including beta-actin, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), hypoxanthine phophoribosyl-transferase (HPRT), ubiquitin (UB) and glucose-6-phosphate dehydrogenase (G6PDH), was determined in a lipopolysaccharide inflammation model in chickens. beta-Actin appeared to be the most stable single gene in our model. Because the use of a single gene for normalization can lead to relatively large errors, the use of the geometric mean of multiple reference genes or normalization factor is preferred. The most stable combination for gene expression analysis in this lipopolysaccharide inflammation model in chickens is G6PDH and UB, since their correlation coefficients were 0.953 and 0.969, respectively (BestKeeper) and an M value of 0.34 and a low V(2/3) value of 0.155 (geNorm) were obtained. The use of HPRT and GAPDH should be avoided. The stable housekeeping genes, G6PDH and UB together, can be used to normalize the expression of pro-inflammatory cytokines in a lipopolysaccharide inflammation model in chickens.     

Expression of genes involved in progesterone receptor paracrine signaling and their effect on litter size in pigs

Background: Embryonic mortality during the period of implantation strongly affects litter size in pigs. Progesterone receptor(PGR) paracrine signaling has been recognized to play a significant role in embryonic implantation. IHH,NR2F2, BMP2, FKBP4 and HAND2 were proved to involve in PGR paracrine signaling. The objective of this study was to evaluate the expression of IHH, NR2F2, BMP2, FKBP4 and HAND2 in endometrium of pregnant sows and to further investigate these genes' effect on litter size in pigs. Real-time PCR, western blot and immunostaining were used to study target genes/proteins expression in endometrium in pigs. RFLP-PCR was used to detect single nucleotide polymorphisms(SNPs) of target genes.Results: The results showed that the m RNA and protein expression levels of IHH, NR2F2 and BMP2 were up-regulated during implantation period(P 0.05 or P 0.01). All target proteins were mainly observed in luminal epithelium and glandular epithelium. Interestingly, the staining of NR2F2 and HAND2 was also strong in stroma. SNPs detection revealed that there was a-204 C A mutation in promoter region of NR2F2 gene. Three genotypes were found in Large White, Landrace and Duroc sows. A total of 1847 litter records from 625 sows genotyped at NR2F2 gene were used to analyze the total number born(TNB) and number born alive(NBA). The study of the effect on litter size suggested that sows with genotype CC tend to have higher litter size.Conclusions: These results showed the expression patterns of genes/proteins involved in PGR paracrine signaling over implantation time. And the candidate gene for litter size was identified from genes involved in this signaling. This study could be a resource for further studies to identify the roles of these genes for embryonic implantation in pigs.     

鹿茸组织中内参基因的筛选和验证

为筛选在不同生长时期鹿茸组织中稳定表达的内参基因,试验以不同生长时期(分别为脱盘后10、20、40和60 d)的鹿茸组织为材料,采用实时荧光定量PCR(qRT-PCR)方法分析甘油醛-3-磷酸脱氢酶(GAPDH)、β2-微球蛋白(B2M)、还原型辅酶Ⅰ(NADH)、60S 核糖体蛋白L40(RPL40)、谷胱甘肽还原酶7(GPx)和β肌动蛋白(ACTB)6个看家基因的表达情况,并运用 geNorm和NormFinder 两个程序综合分析6个看家基因的表达稳定性.结果显示,GAPDH、ACTB、RPL40表达稳定性较好,可用作鹿茸基因表达研究的内参基因,而NADH和GPx的稳定性最差,不适合作内参基因.通过对鹿茸生长相关基因(ANXA5、HSP27、PRD2、CRABP1、LGALS1)表达分析,进一步验证了上述结果,并且发现这5种基因均在脱盘后10 d的鹿茸组织中高表达.该研究结果为鹿茸快速生长及骨化相关基因的研究奠定了一定基础.     

草地早熟禾荧光定量PCR分析中内参基因的筛选

为筛选出草地早熟禾实时荧光定量中的最适内参基因,利用实时荧光定量PCR技术,分析检测6个传统内参基因ACT、GAPDH、UBQ、EF-1α、18s rRNA和β-tublin在草地早熟禾不同组织器官、叶片不同发育期、非生物胁迫和不同激素诱导下mRNA的表达差异情况。利用geNorm、NormFinder和BestKeeper软件综合评价6个候选内参基因的表达稳定性。结果表明,在不同组织、叶片不同发育期、激素诱导和非生物胁迫下,候选内参基因的表达稳定性存在差异。GAPDH在草地早熟禾不同组织器官中表达最为稳定;EF-1α在非生物胁迫下表达最为稳定;不同激素下首选β-tublin;在叶片不同发育期ACT表达最为稳定。综上所述,通过筛选出不同条件下适宜的内参基因不仅有助于提高草地早熟禾基因表达分析的准确性,也为早熟禾属植物其他内参基因的开发提供了理论参考。     

猪VEGF基因5′调控区多态性与产仔数的关联分析

研究通过PCR-SSCP技术对大白猪、长白猪和杜洛克猪共计574头母猪的VEGF基因进行多态分析,并将基因多态性与猪总产仔数(TNB)和产活仔数(NBA)进行关联分析,旨在探讨猪VEGF基因多态性对其产仔数的影响。结果表明:在VEGF 5′调控区内有2个突变位点。P1产物第191位点处由A突变为G,在3个猪品种中只发现AA、AG 2种基因型,其中AG为优势基因型,A为优势等位基因。长白猪第1胎中AG型的TNB和NBA比AA型分别高出1.34头和1.44头(P<0.01),杜洛克猪所有胎次中AG与AA的TNB差异显著(P<0.05),NBA差异极显著(P<0.01)。P2产物第103位点处由C突变为T,在3个猪品种中发现TT、TC、CC 3种基因型,T为优势等位基因。TT、TC分别比CC型的TNB高出2.63头(P<0.05),在杜洛克所有胎次中TC比TT的TNB和NBA分别高出0.84头和0.94头(P<0.05)。P1位点和P2位点能否作为产仔性状的标记基因还需进一步研究。     

Cell-free extract from porcine induced pluripotent stem cells can affect porcine somatic cell nuclear reprogramming

Pretreatment of somatic cells with undifferentiated cell extracts, such as embryonic stem cells and mammalian oocytes, is an attractive alternative method for reprogramming control. The properties of induced pluripotent stem cells (iPSCs) are similar to those of embryonic stem cells; however, no studies have reported somatic cell nuclear reprogramming using iPSC extracts. Therefore, this study aimed to evaluate the effects of porcine iPSC extracts treatment on porcine ear fibroblasts and early development of porcine cloned embryos produced from porcine ear skin fibroblasts pretreated with the porcine iPSC extracts. The Chariot^TM reagent system was used to deliver the iPSC extracts into cultured porcine ear skin fibroblasts. The iPSC extracts-treated cells (iPSC-treated cells) were cultured for 3 days and used for analyzing histone modification and somatic cell nuclear transfer. Compared to the results for nontreated cells, the trimethylation status of histone H3 lysine residue 9 (H3K9) in the iPSC-treated cells significantly decreased. The expression of Jmjd2b, the H3K9 trimethylation-specific demethylase gene, significantly increased in the iPSC-treated cells; conversely, the expression of the proapoptotic genes, Bax and p53, significantly decreased. When the iPSC-treated cells were transferred into enucleated porcine oocytes, no differences were observed in blastocyst development and total cell number in blastocysts compared with the results for control cells. However, H3K9 trimethylation of pronuclear-stage-cloned embryos significantly decreased in the iPSC-treated cells. Additionally, Bax and p53 gene expression in the blastocysts was significantly lower in iPSC-treated cells than in control cells. To our knowledge, this study is the first to show that an extracts of porcine iPSCs can affect histone modification and gene expression in porcine ear skin fibroblasts and cloned embryos.     

In vitro culture of bovine embryos in murine ES cell conditioned media negatively affects expression of pluripotency-related markers OCT4, SOX2 and SSEA1

Despite extensive efforts, establishment of bovine embryonic stem (ES) cell lines has not been successful. We hypothesized that culture conditions for in vitro-produced (IVP) embryos, the most used source of inner cell mass (ICM) to obtain ES cells, might affect their undifferentiated state. Therefore, the aim of this work was to improve pluripotency of IVP blastocysts to produce suitable ICM for further culturing. We tested KSR and foetal calf serum (FCS) supplements in SOF medium and ES cell conditioned medium (CM) on IVC (groups: KSR, KSR CM, FCS and FCS CM). Cleavage and blastocyst rates were similar between all groups. Also, embryonic quality, assessed by apoptosis rates (TUNEL assay), total cell number and ICM percentage did not differ between experimental groups. However, expression of pluripotency-related markers was affected. We detected down-regulation of OCT3/4, SOX2 and SSEA1 in ICM of FCS CM blastocysts (p < 0.05). SOX2 gene expression revealed lower levels (p < 0.05) on KSR CM blastocysts and a remarkable variation in SOX2 mRNA levels on FCS-supplemented blastocysts. In conclusion, pluripotency-related markers tend to decrease after supplementation with ES cell CM, suggesting different mechanisms regulating mouse and bovine pluripotency. KSR supplementation did not differ from FCS, but FCS replacement by KSR may produce blastocysts with stable SOX2 gene expression levels.     

利用实时荧光定量RT-PCR检测鸡A-FABP和H-FABP基因的差异表达

依据鸡A-FABP和H-FABP基因及参照基因GAPDH序列设计引物,以鸡心肌、胸肌和腿肌、肝脏和腹脂总RNA逆转录合成的cDNA为模板,GAPDH基因为参照基因,应用SYBRGreenI实时荧光定量PCR检测如皋黄鸡和安卡红鸡A-FABP和H-FABP基因的差异表达。结果表明:A-FABP、H-FABP基因和参照基因GAPDH基因融解曲线为单峰,无杂峰及二聚体,其扩增效率分别为99.7%、99.8%和100.0%。如皋黄鸡H-FABP基因在心肌、胸肌和腿肌的差异表达量分别是安卡红鸡的0.0860、0.0680倍和0.0580倍(P0.05)。H-FABP基因mRNA表达量与肌内脂肪含量呈显著负相关。如皋黄鸡A-FABP基因在腹脂和肝脏的表达量分别是安卡红鸡的15.9640倍和10.9640倍(P0.05),而在心肌、胸肌和腿肌的表达量差异不显著。     

Glyoxalase 1 expression is downregulated in preimplantation blastocysts of diabetic rabbits

In a diabetic pregnancy, an altered maternal metabolism led to increased formation of reactive α‐dicarbonyls such as glyoxal (GO) and methylglyoxal (MGO) in the reproductive organs and embryos. The enzyme glyoxalase (GLO) 1 detoxifies reactive α‐dicarbonyls thus protecting cells against malfunction or modifications of proteins by advanced glycated end products (AGEs). The aim of this study was to analyse the influence of a maternal insulin‐dependent diabetes mellitus (IDD) on GLO1 expression and activity in preimplantation embryos in vivo and human trophoblast cells (Ac‐1M88) in vitro. Maternal diabetes was induced in female rabbits by alloxan before conception and maintained during the preimplantation period. GLO1 expression and activity were investigated in 6‐day‐old blastocysts from healthy and diabetic rabbits. Furthermore, blastocysts and human trophoblast cells were exposed in vitro to hyperglycaemia, GO and MGO and analysed for GLO1 expression and activity. During gastrulation, GLO1 was expressed in all compartments of the rabbit blastocyst. Maternal diabetes decreased embryonic GLO1 protein amount by approx. 30 per cent whereas the enzymatic activity remained unchanged, indicating that the specific GLO1 activity increases along with metabolic changes. In in vitro cultured embryos, neither hyperglycaemia nor MGO and GO had an effect on GLO1 protein amount. In human trophoblast cells, a stimulating effect on the GLO1 expression was shown in the highest GO concentration, only. Our data show that maternal diabetes mellitus affects the specific activity of GLO1, indicating that GLO1 was post‐translationally modified due to changes in metabolic processes in the preimplantation embryos.