Molecular Clone, Expression, and Prediction of Construction and Function to Key Genes of Interleukin Family of Porcine

This research was to clone, express, and analyze the structure and function of major molecules of porcine interleukin family. Genes of porcine interleukin family were cloned by RT-PCR from stimulated porcine PBMC by LPS and PHA, and then expressed in E. coli, and the structure and function of these molecules were predicted by ExPASY. The results showed that genes of IL-4, IL-6, and IL-18 were successfully cloned and expressed. Furthermore, the expression products of recombinant IL-4 and IL-6 both have multiple biological activities. By analyzing these genes with the NCBI/GenBank data, the homologies of the nucleotide acid sequence are 99.25, 99.21, and 100%, respectively, and have great species differences when compared with other animal species. The results of the prediction showed that all these molecules contain several phosphorylation, glycosylation, protein kinase, and signal transduction bonding sites in secondary structure, and all are compact globularity protein in space configuration. These characteristics of structure are the basis for their multiple biological functions. The genes, structure and function of key molecular of porcine interleukin family were successfully cloned, expressed, and analyzed in this paper.

Fusion of EGFP and porcine α 1,3GT genes decrease GFP expression

Objective:To investigate the effect of fusion proteins expressed by the fused gene of porcineα1,3 galactosyltransierase(α1,3 GT) and enhanced green fluorescent protein(EGFP) on the green fluorescence intensity of EGFP.Methods:The fragment containingα1.3GT was firstly recovered after the pcDNA3.1-α1.3GT recombinant vector were digested with BamHl and EcoRI,and then,the resultant fragment was ligated to the pEGFP-N1 vector which was also digested with the same enzymes.The new recombinant eukaryotic expression pEGFP/a 1,3GT vector was obtained and sequenced.The pEGFP/α1,3GT was used to transfect human lung carcinoma cells A549 and HEKC 293FT,and the expression of EGFP was quantitatively analyzed by fluorescent microscope and flow cytometry.Results:The positive percentage of A549 was 80.5%,and that of 293 FT was 86.5%48 hours after the two cell lines both were transfected by pEGFP-N1.The positive percentage of A549 was 75.8%,and that of 293 FT was 81.2%48 hours after the two cell lines were transfected by pEGFP/α1.3GT.The mean fluorescence intensities of A549 transfected with pEGFP-N1 and pEGFP/α1.3GT were 1.21 and 0.956,respectively when compared with that of A549 without transfection.Meanwhile,the those of the 293FT that were transfected with pEGFP-N1 and pEGFP/αl,3GT were 7.66 and 1.00.respectively when compared with that of 293FT cells without transfection.Conclusions:These results suggested that the expression of EGFP gene fused with porcineα1,3GT gene was partly inhibited.

Study on the Function of ORF Genes of Porcine Circovirus-like Virus P1

[Objectives]This study was conducted to determine the functions of eight ORF genes of porcine circovirus-like virus P1.[Methods]The double-copy tandem molecular cloning of porcine circovirus-like virus P1 genome was used to construct molecular clones with eight ORFs deleted by DNA site-directed mutagenesis technology.After transfected into PK15 cells for a certain period of time,RNA were extracted and was used to verify whether the eight ORFs were deleted or not and used for gene microarry analysis.The GO functions and KEGG pathway enrichment of differentially expressed genes were analyzed.[Results]P1 ORF1 is mainly involved in the biological processes of defense response to virus,signal transduction,regulation of Rab GTPase activity,and lipid metabolic process,and involved in the molecular functions of protein phosphatase inhibitor activity,phosphatidylinositol phospholipase C activity,2 iron,2 sulfur cluster binding,phosphoric diester hydrolase activity,and Rab GTPase activator activity,and in the KEGG pathways of secretion of digestive gland and nervous system development.P1 ORF2 is mainly involved in the biological processes of positive regulation of leukocyte chemotaxis,positive regulation of cell proliferation,positive regulation of cell migration,defense response to virus,regulation of cell growth,and involved in the molecular functions of insulin-like growth factor binding,and chemokine activity,and in the KEGG pathways of cytosolic DNA-sensing pathway,RIG-I-like receptor signaling pathway,toll-like receptor signaling pathway,chemokine signaling pathway,and cytokines,cytokine-cytokine receptor interaction.The biological processes,molecular functions and related pathways involving P1 ORF3 and ORF5 are basically similar to those of ORF2.P1 ORF8 is mainly involved in the biological processes of purine ribonucleotide biosynthetic process,amino acid transport,defense response to virus,amino acid transmembrane transport,and involved in molecular functions of N6-(1,2-dicarboxyethyl)AMP AMP-lyase(fumarate-forming)activity,iron-sulfur cluster binding,amino acid transmembrane transporter activity.[Conclusions]The analysis of the ORF functions of P1 virus lays a foundation for the study of its pathogenicity and pathogenesis.

Expression of Porcine Reproductive and Respiratory Syndrome Virus ORF7 Gene and Purification and Immunological Activity Analysis of the Recombinant Protein

[Objective] The aim of this study was to realize efficient expression of the porcine reproductive and respiratory syndrome virus （PRRSV） ORF7 gene in genetic engineering bacteria and analYze the immunological activity of the recombinant protein after purification. [ Method] The constructed recombinant expression vector pET-ORF7 was transformed into Escherichia co1BL21 （DE3） and induced by IPTG under the optimal condition. After analysis of SDS-PAGE and Western Blot, the expression products were purified by Ni-NTA His · Bind Resin chrom- atographic column under denaturing condition and renatured by gradient dialysis. Subsequently, the immunological activity of the renatured recombinant protein was detected by Westem Blot and indirect ELISA. [ Result] The recombinant plasmid pET-ORF7 expressed in E. coli successfully, and the fusion protein was in the form of inclusion body. By SDS-PAGE detection, the molecular weight of the expression protein was approximate 33 kD, according with the expectation. Analysis by Bandscan software showed that the expressed fusion protein was about 50% of total bacterial protein of BL21 （DE3）. Wastem Blot and indirect ELISA detection showed that the renatured protein could react with PRRSV positive serum specifically, indicating its good immunological activity. [ Conclusion] This study lays a foundation for the preparation of PRRSV monoclonal antibody and diagnostic kit.

Analysis on Heredity and Variation of the ORF_5 Gene of Prevalence Strains Porcine Reproductive and Respiratory Syndrome Virus

[ Objective] The aim was to analyze the reason and epidemic trend of PRRSV, and provide theoretical basis for preventing and controlling PRRS. [Methed]According to the sequence of ATCC VR-2332 strain porcine reproductive and respiratory syndrome virus published by the GenBank, the primers were designed and synthesized. ORF5 gene sequences of seven prevalence strains were amplified by RT-PCR. The sequences of ORF5 genes were analyzed by DNAStar and compared with those of ATCC VR-2332, CH-1 a, B J-4, LV-M96262 and MLV vaccine strains, phylogenetic tree among isolates was analyzed. [Result] Analysis of nucleotide sequence showed that the homology was 88.1% - 98.8%, 89.9% -95.2%, 85.6% -98.7% between ORF5 genes of seven prevalence strains and VR-2332, CH-1a, BJ-4, and the homology was 54.7% -56.9% between ORF5 genes and LV. Analysis of amino acid sequence showed that the homology was 88.1% -96.8%, 88.1% - 94.5%, 86.1% -96.5% between ORF5 genes of seven prevalence strains and VR-2332, CH-1a, bBJ-4, the homology was 54.7% -56.2% between the ORF5 genes and LV.[ Conclusion] The variation of prevalence strains was great in the ORF5 gene region, the homology of ORF5 gene sequence was higher and genetic relationship was nearer during prevalence strains in the same region, or was far in different regions.

Differential Expression of APOEGene in Porcine Fetal Fibroblast Cells

[Objective]The aim was to study the differential expression ofAPOEgene in different generations of porcine fetal fibroblasts cells.[Method]The first,tenth,fifteenth,twentieth,twenty-fifth,fiftieth generations of porcine fetal fibroblast cells,which were normally grown and passed,were collected before total RNA was extracted respectively.The expression ofAPOEgene in different generations of porcine fetal fibro-blast cells was detected by RT-PCR technique.[Result]The expression level of porcine APOE mRNA in the first generation of porcine fetal fi-broblast cells was the highest,and then it gradually decreased with the increase of cell generations and was the lowest in the fiftieth generation.[Conclusion]The expression ofAPOEgene had the selective trend in different generations of porcine fetal fibroblast cells.

Cloning and Prokaryotic Expression of NS1 Gene of Porcine Parvovirus (PPV) SD1 Strain

[Objective] The research aimed to provide the theoretical basis for establishing a rapid diagnosis method for porcine parvovirus（PPV）. [ Method] One pair of primers were designed according to PPV genome sequences on GenBank website and the sequences of prokaryotic expression vector pET30a （ ＋ ） with multiple cloning sites. The whole sequence of NS1 gene in PPV SD1 strain was amplified by using PCR technology and the positive recombinant plasmid was analyzed by sequencing and homology comparison. The prokaryotic expression recombinant plasmid PET30a/NS1 was constructed to make its induction expression in Escherichia coll. [ Result] The target fragment with the length of 2 208 bp was obtained from PCR amplification. The nucleotide homologies between the cloned NS1 gene and the reported relevant PPV genes were from 97.3 % to 99.4 %, which indicated that NS1 gene had high conservation. But it had a 12-basepair successive deletion near the hydroxyl end. The cloned PPV NS1 gene was successfully expressed in prokaryotic cell, and its expression products existed mostly in inclusion bodies. [ Conclusion] The results of SDS-PAGE detection showed that the molecular weight of PPV NS1 protein was 86 KD.

Cloning and Functional Analysis of the Porcine Growth Hormone Gene Promoter

[Objective] This study aimed to clone the porcine growth hormone gene promoter and determine the core promoter sequences and the cis-acting elements. [Method] Sequence of the 5＇flanking region of porcine growth hormone gene was searched out and downloaded from the NCBI website. According to the targeted se- quence, primers were designed and synthesized for the PCR amplification. The 1 882 bp （-1 821 bp-＋61 bp） fragment was amplified by PCR. Nine promoter frag- ments with different lengths were obtained by genome-walking deletion method and then cloned into luciferase reporter vectors. Relative transcriptional activities of these 5＇ terminal-deleted plasmids in pituitary and non-pituitary cells were determined by transient transfection of the rat pituitary adenoma cell （GH3）, porcine lilac endotheli- um cell （PIEC） and porcrne Kidney-15 （PK15） with the constructed dual-luciferase vectors. [Result] Result of DNA sequencing showed that the 1 882 bp fragment of GH 5＇ promoter was successfully cloned. Nine luciferase reporter gene plasmids were constructed. DuaI-Luciferase reporter assay indicated that the promoter inserted into reporter gene vector had very strong cell specificity. [Conclusion] Porcine growth hormone gene specifically expresses in pituitary cells. The minimal promoter of the porcine growth hormone gene is mapped at the region -110 bp-＋61 bp. Promoter regions 218 bp--110 bp and -429 bp--218 bp contain positive regulatory elements.

Acute Toxicity of Recombinant Porcine Interferon-alpha

To observe the acute toxicity of recombinant porcine interferen-alpha （IFN-alpha） in mice and thus provide a basis for the clinical safety. [Method] According to the principles of acute toxicity, all the mice were divided into two major groups （intraperitoneally injected group and intramuscularly injected group） respectively at high dose, moderate dose and low dose. And the normal control group was also set up. Within 14 d after administration, the behavior of mouse and the degree of toxicity were continuously observed. The hematological indexes and biochemical indexes of blood were detected to obtain the preliminary toxicity data of the recombinant porcine IFN-alpha. And at the end of the experiment, mice were sacrificed for autopsy. [ Result] There was not significant difference in external performance, behavioral characteristics, body temperature, weight, pathological anatomy of visceral organs, hematological indexes and biochemical indexes between the experimental groups and the control group. [ Conclusion] The highest dose of porcine interferon （5.0 x 10s IU per mouse） in this experiment or the dose lower than this dosage should not have significant toxic effects on mice, and the recombinant porcine IFN-alpha is safe in clinical application.

Genetic Variation Analysis of 3D Gene and Molecular Detection of Porcine Kobuvirus in 2013-2014

[Objective] This study aimed to investigate the prevalence and variation of porcine kobuvirus （PKV） in suckling piglets in China. [Method] In 2013-2014, 224 feces samples from suckling piglets with diarrhea in 27 pig farms of five provinces in China were collected to detect 3D genes of PKV with RT-PCR method; the sequences and genetic variation of 29 PKV 3D genes were analyzed. [Result] Total positive rate of PKV in feces samples from suckling piglets with diarrhea was 65.18% （146/224）; total positive rate of PKV in pig farms was 85,2% （23/27）; nucleotide sequences and the deduced amino acid sequences of 29 PKV 3D genes shared 87.0%-100% and 92.7%-100% homologies with six PKV-related 3D sequences, respectively. [Conclusion] PKV infection is prevalent in suckling piglets in China; PKV 3D genes exhibit high diversity.

Genetic Variation of the ORF5 Gene of Porcine Reproductive and Respiratory Syndrome Virus in East China during 2008-2010

[Objective] A total of 260 swine samples of dead or sick pigs collected from 7 provinces （municipalities） Jiangsu, Anhui, Shanghai, Shandong, Zhejiang, Fujian and Jiangxi of China during 2008-2010 were detected for porcine reproductive and respiratory syndrome virus （PRRSV）. And the ORF5 genes of some isolates were amplified and sequenced for understanding the molecule epidemiology and the genetic evolution of PRRSV in East China. [Method] Using RT-PCR method, PRRSV was detected by RT-PCR from samples. The complete ORF5 genes of 36 PRRSV positive samples was amplified, sequenced and analyzed with other 15 strains available on GenBank. [Result] PRRSV was detected in 118/260 of the clinical samples, with a positive rate was 45.4%. Sequence analysis showed that the 36 isolates of this study belonged to the North American-type PRRSV strains and were closely related to the highly pathogenic PRRSV （HP-PRRSV） with 94.6%-100% amino acid sequence identities. The sequence analysis combined with the phylogenetic analysis indicated that all these North American-type PRRSV strains in East China were further divided into five subgenotypes, subgenotype Ⅲ showed closer identity with HPPRRSV; almost all subgenotypes were found to be variable in the primary neutralizing epitope; subgenotypes Ⅲ and IV had more glycosylation sites than others. Although these 36 isolates were collected from different provinces in East China, there were no obvious relations between the distribution of PRRSV and the region. [Conclusion] The PRRSV infection was widespread and HP-PRRSV was the popular strain in East China during 2008-2010. However some different genetic characteristics appeared in the genomes, the genetic evolution was relatively stable. There exists a cross-cutting phenomenon on the genetic relationship of PRRSV isolates obtained from different provinces. Subgenotypes IV and V only appeared in some provinces, but the distribution of PRRSV did not show apparent geographical characteristics.

miR-10b promotes porcine immature Sertoli cell proliferation by targeting the DAZAP1 gene

MicroRNAs(miRNAs) have been widely identified in porcine testicular tissues and implicated as crucial regulators of proliferation, apoptosis, and differentiation in porcine spermatogenesis related cells. However, the function roles of most of the miRNAs that have been identified in Sertoli cells are poorly understood. In the present study, six experiments were conducted to study the regulatory role of miR-10b in porcine immature Sertoli cells. In experiment 1, the results showed that the relative mRNA expression level of miR-10b in porcine testicular tissues decreased quadratically(P<0.001) with increasing age, while the relative mRNA expression level of DAZAP1 gene increased(P<0.001). In addition, the mRNA expression of miR-10b was negatively(P<0.01) correlated with DAZAP1 mRNA expression(r=–0.550). In experiment 2, the results from the bioinformatic analysis and a luciferase reporter assay demonstrated that miR-10b directly targeted the DAZAP1 gene in porcine immature Sertoli cells. DAZAP1 mRNA and protein expressions were both regulated(P<0.05) by miR-10b. In experiments 3 to 5, the over-expression of miR-10b or the siRNA-mediated knockdown of the DAZAP1 gene promoted(P<0.05) porcine immature Sertoli cell proliferation, as determined by the Cell Counting Kit-8(CCK-8) assay and the 5-Ethynyl-2′-deoxyuridine(EdU) assay. However, an annexin V-FITC/PI staining assay and the expression of cell survival-related genes indicated that over-expression of miR-10b or knockdown of DAZAP1 had no effect(P>0.05) on porcine immature Sertoli cell apoptosis. In experiment 6, the co-transfection treatment results showed that miR-10b promoted(P<0.05) porcine immature Sertoli cell proliferation by targeting DAZAP1 gene. Overall, these experiments demonstrated that miR-10b promotes porcine immature Sertoli cell proliferation by targeting the DAZAP1 gene.

Detection of Porcine Epidemic Diarrhea Virus in Guangxi Province from 2011 to 2014 and Sequence Analysis of Its M Gene

Detection of pigs epidemic diarrhea virus （PEDV） was conducted on 331 piglets diarrhea fecal samples collected in Nanning, Yulin and other 12 areas of Guangxi Province from January of 2011 to April of 2014 by the method of reverse transcription-polymerase chain reaction （RT-PCR）. The results showed that the positive samples of PEDV were 210 and the positive rate was 63.44%. The clone and sequencing of M gene was carried out on 25 positive samples. PEDV reference strains were selected from GeneBank to conduct the sequence homology alignment analysis and the phylogenetic tree of M gene. The M gene homology and amino acid sequence identity between 25 isolated strains and 51 reference strains were 96.0% - 99.6% and 94.3% - 99.6%, respectively. The genetic variation anal- ysis of M gene showed that the genetic relationship of PEDV prevalent strains in Guangxi Province from 2013 to 2014 was close to that of the prevalent strains in Bei- jing, Anhui, Wuhan, Hebei and Guangdong from 2010 to 2013, and which were far from that of the Chinese early isolates CH/S （GenBank number： JN547228 ）, vaccine strain CV777 （GenBank number： AF353511 ） and Attenuated DR13 （GenBank number： JQ023162）. Indicating that the PEDV strains prevalent in Guan- gxi in recent years showed significant variation with the early isolates.

Long non-coding RNA FPFSC promotes immature porcine Sertoli cell growth through modulating the miR-326/EHMT2 axis

Sertoli cells are indispensable for guaranteeing normal spermatogenesis and male fertility.Although a huge number of long non-coding RNAs(lncRNAs)are identified from developing porcine testicular tissues and have been predicted with crucial regulatory roles in spermatogenesis,their functions and regulatory mechanisms are still in infancy.Herein,we mainly explored the regulatory and functional roles of lncFPFSC in proliferation and apoptosis of immature porcine Sertoli cells.The results demonstrated that lncFPFSC was predominantly located in the cytoplasm of immature porcine Sertoli cells.lncFPFSC overexpression promoted cell cycle progression and cell proliferation,as well as inhibited cell apoptosis,whereas siRNA-induced lncFPFSC knockdown resulted in the opposite effects.Mechanistically,lncFPFSC acted as a sponge for miR-326.Overexpression of miR-326 inhibited cell proliferation and induced cell apoptosis,which further abolished the effects of lncFPFSC overexpression.The euchromatic histone-lysine N-methyltransferase 2(EHMT2)gene was directly targeted by miR-326,and its mRNA and protein expressions were both negatively regulated by miR-326 in immature porcine Sertoli cells.Then,siRNA-induced EHMT2 knockdown resulted a similar effect of miR-326 inhibition.Collectively,lncFPFSC promoted proliferation and inhibited apoptosis in immature porcine Sertoli cells through modulating the miR-326/EHMT2 axis.This study expanded our understanding of non-coding RNAs in participating porcine spermatogenesis through deciding the fate of Sertoli cells,and the competing endogenous RNA(ceRNA)network,and provided new molecular markers to treat Sertoli cell disorder inducing male infertility.

Study on the Polymorphisms of Porcine Myostatin Gene in Promoter Region by PCR-RFLPS

In order to further study functions of the porcine myostatin gene, we analyzed the polymorphisms of porcine myostatin gene in promoter region among different breeds including Yorkshire, Landrace, Duroc, Junmu, Min pig and Sanjiang white pig by PCR-RFLPs. The allele T dominated in the imported lean-type pig breeds such as Yorkshire, Landrace and Duroc. No allele A was detected in Junmu and Sanjiang white pig, and the frequencies of three genotypes were about equal in Min pig. The result using X2 analysis showed that the distribution of three genotypes was related to pig breeds.

Attenuation of Virulent Porcine Reproductive and Respiratory Syndrome Virus Strain CH-1a and Genetic Variation of ORF5 Gene

To develop a modified live vaccine （MLV） against porcine reproductive and respiratory syndrome virus （PRRSV）, virulent CH-Ia strain was attenuated by serial passages up to 130 passage （P130） in Marc-145 cells. The virulence and immune efficacy of the attenuated CH-1 a were evaluated in pigs. The results showed that animals inoculated with P130 did not develop any clinical sign of the disease, but produced rapid and effective humoral immune responses against PRRSV challenge, indicating that attenuated CH-1 a P 130 is the candidate as the effective vaccine against PRRSV. To define the potential mutations in the attenuated CH-la genome, we sequenced and analyzed the ORF5 gene of CH-la strain of different passages （P39, P55, P65, P70, P85, P100, P115, P120, P125, and P130） and found that three mutations （C5Y, H38Q and L146Q） which may be related with the attenuation of CH-la. In addition, we also found a unique restriction enzyme site （TspEI） in the ORF5 gene of attenuated CH-la, which can be used as a genetic marker to distinguish original and attenuated CH- 1 a.

Expression of Porcine Interleukin-2 and Porcine Interleukin-6 and Their Adjuvant Effects on Gene Deleted Vaccine of Pseudorabies Virus(TK^-/gG^-/LacZ^+)

Porcine interleukin-2 and porcine interleukin-6 cDNA sequences were cloned into the expressing vectors pET-28a and pGEX-KG respectively. They were expressed in E. coli BL21(DE3)with high-level production. The gene deleted vaccine of pseudorabies virus Ea strain(TK-/gG-/LacZ+)was mixed with the two different purified recombinant proteins each, or both, with the doses of 2, 5 or 10 μg ml-1. Ten groups of pseudorabies negative antibody swines were immuned twice with tested vaccines with different doses, or control vaccine, respectively. The antibody liters of the test groups were detected by neutralization test, and the daily weight gains of swines were calculated and analyzed statistically. In the study, all the neutralizing antibody ti-ters in test groups were higher than the control group, and the recombinant proteins appeared a dose dependent adjuvant effect. The tested vaccines with 2 μg ml-1 pIL-2 and with 10 μg ml-1 pIL-2/pIL-6 got significant and extremely significant differences, compared with the vaccines without pILs. The difference of the daily weight gain indicated the potential positive influence of pIL-2 and pIL-6 on immune protection.

Expression of Porcine Circovirus Type 2 ORF2 Gene in Myocardial Cells of Detached Cherry Valley Duck

The objective of this study was to construct the recombinant eukaryotic expression plasmid of ORF2 gene harboring enhanced green fluorescent protein （EGFP） report gene. ORF2 gene of porcine circovirus type 2 cloned by PCR was ligated to the expression vector pEGFP-N1, which contains enhanced green fluorescent protein （EGFP） report gene, the recombinant eukaryotic expression plasmid pEGFP-N1-ORF2 was constructed successfully and was transfected into pre- pared duck myocardial cells （DMCs） by lipofectin. According to the result, the fluorescence expression was directly detected with fluorescence microscope, and the expression of ORF2 were analyzed by RT-PCR and indirect immunofluorescence assay （IFA） respectively. About 48 h after transfection, green fluorescent can be observed on transfected cells ： T-PCR and IFA were positive. This indicated that ORF2 gene of PCV2 was expressed efficiently in transfected duck myocardial cells.

Purification of Recombinant Porcine Interferon-Alpha

[ Objective] To study the purification of recombinant porcine interferon-alpha （rPolFN-alpha） and lay a foundation for researches on the structure of the rPolFN-alpha and the preparation of standard proteins. [ Method] The rPolFN-alpha were induced and extracted from the recombi- nant E. coil BL21, and they were purified by two strategies. The first strategy was that the rPolFN-alpha were purified by GST （ glutathione S transferase） affinity chromatography, DEAE （diethylaminoethyl） anion exchange chromatography and gel filtration in turn defined as three-step chromatography method; the second strategy was that the rPolFN-alpha were purified by GST affinity chromatography and gel filtration in tum defined as two-step chromatography method. Then the purified products were detected by the SDS-PAGE （sodium dodecyl sulfate polyacrylamide gel electrophoresis） and were identified by western-blotting. [Result] The purity quotient of pudfied products of the two-step chromatography method was 96.0% and that of the three-step chromatography method was 98.8%. The purified products were detected by the SDS-PAGE and the western- blotting, respectively. The results showed that the target band was 45.0 kDa and the specific band was found. [ Conclusion] The purity quotient of proteins of the two-step chromatography method is close to that of the three-step chromatography method, thus the two-step chromatography meth- od is more convenient and more suitable for pilot production than the three-step chromatography method.

Unveiling how vitrification affects the porcine blastocyst: clues from a transcriptomic study

Background:Currently,there is a high demand for efficient pig embryo cryopreservation procedures in the porcine industry as well as for genetic diversity preservation and research purposes.To date,vitrification(VIT)is the most efficient method for pig embryo cryopreservation.Despite a high number of embryos survives in vitro after vitrification/warming procedures,the in vivo embryo survival rates after embryo transfer are variable among laboratories.So far,most studies have focused on cryoprotective agents and devices,while the VIT effects on porcine embryonic gene expression remained unclear.The few studies performed were based on vitrified/warmed embryos that were cultured in vitro(IVC)to allow them to re–expand.Thus,the specific alterations of VIT,IVC,and the cumulative effect of both remained unknown.To unveil the VIT-specific embryonic alterations,gene expression in VIT versus(vs.)IVC embryos was analyzed.Additionally,changes derived from both VIT and IVC vs.control embryos(CO)were analyzed to confirm the VIT embryonic alterations.Three groups of in vivo embryos at the blastocyst stage were analyzed by RNA–sequencing:(1)VIT embryos(vitrified/warmed and cultured in vitro),(2)IVC embryos and(3)CO embryos.Results:RNA–sequencing revealed three clearly different mRNA profiles for VIT,IVC and CO embryos.Comparative analysis of mRNA profiles between VIT and IVC identified 321,differentially expressed genes(DEG)(FDR<0.006).In VIT vs.CO and IVC vs.CO,1901 and 1519 DEG were found,respectively,with an overlap of 1045 genes.VIT-specific functional alterations were associated to response to osmotic stress,response to hormones,and developmental growth.While alterations in response to hypoxia and mitophagy were related to the sum of VIT and IVC effects.Conclusions:Our findings revealed new insights into the VIT procedure-specific alterations of embryonic gene expression by first comparing differences in VIT vs.IVC embryos and second by an integrative transcriptome analysis including in vivo control embryos.The identified VIT alterations might reflect the transcriptional signature of the embryo cryodamage but also the embryo healing process overcoming the VIT impacts.Selected validated genes were pointed as potential biomarkers that may help to improve vitrification.