Polymorphism and expression of the porcine Tenascin C gene associated with meat and carcass quality

The research aimed to screen for polymorphism, expression of Tenascin C (TNC) and association with meat and carcass quality traits. Three single nucleotide polymorphisms were detected. In a Duroc×Pietrain F2 cross (DuPi) population, g.44488C>T was associated with meat color and ham weight; g.68794A>G was associated with pH at 24h post mortem in ham (pH24(H)) and muscle area but g.68841C>T was not statistically associated. Genotyping in a commercial Pietrain (Pi) population showed that g.44488C>T was associated with pH24(H), whereas g.68794A>G was associated with conductivity at 45 min post mortem in loin and backfat thickness. Diplotypes showed significant effects on pH24(H) in both populations. The expression was associated with pH at 45 min post mortem in loin and cooking loss. TNC was significantly higher in animals with higher muscle pH. Linkage analysis revealed four trans-regulated eQTL on four autosomes. These results suggest that TNC could be a potential candidate gene for meat quality traits in pigs.

Intracellular signaling cascades induced by relaxin in the stimulation of capacitation and acrosome reaction in fresh and frozen-thawed bovine spermatozoa

Relaxin is one of the 6-kDa peptide hormones, which acts as a pleiotropic endocrine and paracrine factor. Our previous studies revealed that sperm capacitating medium containing relaxin induced capacitation and acrosome reaction (AR) in fresh and frozen-thawed porcine or bovine spermatozoa. However, the intracellular signaling cascades involved with capacitation or AR induced by relaxin was unknown. Therefore, the present study was designed to investigate the intracellular signaling cascades involved with capacitation and AR induced by relaxin in fresh and frozen-thawed bovine spermatozoa. Spermatozoa were incubated in sperm Tyrode's albumin lactate pyruvate (Sp-TALP) medium supplemented with (40 ng ml(-1)) or without relaxin, and subjected to evaluation of chlortetracycline staining pattern, cholesterol efflux, Ca(2+)-influx, intracellular cyclic adenosine monophosphate (cAMP) and protein tyrosine phosphorylation. Capacitation and AR were increased (P<0.05) in both fresh and frozen-thawed spermatozoa incubated with relaxin. Cholesterol effluxes were greater in the fresh (P<0.01) and frozen-thawed (P<0.05) spermatozoa incubated with relaxin than the spermatozoa incubated without relaxin. Ca(2+)-influxes were also significantly stimulated by relaxin in the fresh (P<0.01) and frozen-thawed (P<0.05) spermatozoa. The Sp-TALP medium containing relaxin influenced the generation of intracellular cAMP in the fresh (P<0.01) and frozen-thawed (P<0.05) spermatozoa, and exhibited higher exposure of protein tyrosine phosphorylation in both sperm types than the medium devoid of relaxin. Therefore, the results postulate that relaxin exerts the intracellular signaling cascades involved with capacitation and AR through accelerating the cholesterol efflux, Ca(2+)-influx, intracellular cAMP and protein tyrosine phosphorylation in fresh and frozen-thawed bovine spermatozoa.

Gelatinase activities and haptoglobin concentrations in healthy and in degenerative articular cartilage of pigs

The objectives of this study were to investigate the activity of the matrix metalloproteinase (MMP)-2 and MMP-9 in healthy and in degenerative cartilage and to characterize the relation with the acute phase protein haptoglobin (HP) in articular cartilages of pigs. Joint surfaces of the proximal and distal humerus and femur of fattening pigs were histopathologically classified. In addition, cartilage homogenates and synovia were obtained. The tissue homogenates were analysed for gelatinase activity by zymography and by activity assay. The concentrations of HP in cartilage homogenates, in synovia and in serum were analysed by ELISA. High enzymatic activity of the MMP-2 latent form was observed in zymography in all samples. Zymographic activities of MMP-2 active form and MMP-9 (active and latent form) were detected at low levels in some samples. Comparison of the zymographic activities of gelatinases in unaltered vs. altered cartilages yielded no differences. In contrast to zymography, cartilage homogenates were negative for MMP-2 and MMP-9 in the activity assays. The concentrations of HP in cartilage homogenates and in synovia from samples without alteration and from samples with massive alterations were not different. When classified according to their HP concentration, cartilage homogenates with increased HP concentrations had higher (p < 0.05) zymographic activities of the MMP-2 active form. For the two MMPs investigated, there was no detectable relationship with degenerative processes in the cartilage.

Quantitative trait loci analysis for leg weakness-related traits in a Duroc × Pietrain crossbred population

Background

Leg weakness issues are a great concern for the pig breeding industry, especially with regard to animal welfare. Traits associated with leg weakness are partly influenced by the genetic background of the animals but the genetic basis of these traits is not yet fully understood. The aim of this study was to identify quantitative trait loci (QTL) affecting leg weakness in pigs.

Methods

Three hundred and ten F₂ pigs from a Duroc × Pietrain resource population were genotyped using 82 genetic markers. Front and rear legs and feet scores were based on the standard scoring system. Osteochondrosis lesions were examined histologically at the head and the condylus medialis of the left femur and humerus. Bone mineral density, bone mineral content and bone mineral area were measured in the whole ulna and radius bones using dual energy X-ray absorptiometry. A line-cross model was applied to determine QTL regions associated with leg weakness using the QTL Express software.

Results

Eleven QTL affecting leg weakness were identified on eight autosomes. All QTL reached the 5% chromosome-wide significance level. Three QTL were associated with osteochondrosis on the humerus end, two with the fore feet score and two with the rear leg score. QTL on SSC2 and SSC3 influencing bone mineral content and bone mineral density, respectively, reached the 5% genome-wide significance level.

Conclusions

Our results confirm previous studies and provide information on new QTL associated with leg weakness in pigs. These results contribute towards a better understanding of the genetic background of leg weakness in pigs.

Evaluation of bovine zona pellucida characteristics in polarized light as a prognostic marker for embryonic developmental potential

It has previously been demonstrated that zona pellucida imaging of human oocytes using polarized light microscopy is a clinically applicable method for the noninvasive assessment of oocyte quality. This study was designed to investigate whether zona pellucida characteristics of bovine oocytes and zygotes in polarized light may similarly serve as a useful marker for developmental competence in bovine reproductive biotechnologies. Zona birefringence intensity parameters of 2862 oocytes/zygotes were objectively evaluated with an automatic analysis system and correlated with oocyte/zygote quality. In detail, immature oocytes of good quality assessed with brilliant cresyl blue staining showed significantly lower zona birefringence than poor-quality counterparts (P<0.001). After in vitro maturation and classification according to maturational status, the birefringence intensity parameters were significantly different in those oocytes that reached metaphase II compared with arrested stages (P<0.001). Following either parthenogenetic activation or IVF with subsequent in vitro culture in a well-of-the-well system until day 9, superior development as determined by cleavage, blastocyst formation, and hatching ability was associated with lower zona birefringence intensity parameters. When early zygote-stage embryos were selected and assorted in groups based on zona birefringence (high/medium/low), the group of embryos derived from high-birefringence zygotes displayed a significantly compromised developmental potential compared with low-birefringence zygotes. These results clearly show that developmentally competent bovine oocytes/zygotes exhibit lower zona birefringence intensity parameters. Therefore, birefringence imaging of zona pellucida is a suitable technique to predict bovine preimplantation embryo development.

Investigation on interferon alpha-inducible protein 6 (IFI6) gene as a candidate for meat and carcass quality in pig

The aim of this research was to screen for polymorphism and to perform an association study of IFI6 with meat and carcass quality traits. A SNP (g.370A>G) was detected which was associated (P<0.05) with meat colour, pH 24h post mortem (p.m.) in ham, conductivity 45 min p.m. in loin and conductivity 24 h p.m. in ham, drip loss and carcass length in Duroc x Pietrain and with meat colour, muscle area and ham percentage in the Pietrain population. Highest expression of IFI6 mRNA was detected in skeletal muscle (longissimus dorsi) by qRT-PCR comparing different tissues. Both qRT-PCR and western blot revealed that the IFI6 gene and protein expressions were significantly (P<0.05) higher in skeletal muscle with low drip loss compared to that of high drip loss. IFI6 protein was localized in the myocytes membrane. Results suggested that IFI6 might play roles in meat and carcass quality and is a potential positional, physiological and functional candidate gene for improving meat quality traits in pigs.

Association study and expression analysis of CD9 as candidate gene for boar sperm quality and fertility traits

Cluster-of-differentiation antigen 9 (CD9) gene expressed in the male germ line stem cells is crucial for sperm-egg fusion, and was therefore selected as candidate gene for boar semen quality. The association of CD9 with boar sperm quality and fertility trait was analyzed using a total of 340 boars both from purebred Pietrain and Pietrain×Hampshire crosses. A single nucleotide polymorphism (g.358A>T) in intron 6 was significantly associated with sperm motility (MOT) (P<0.001), plasma droplet rate (PDR) (P<0.001) and abnormal spermatozoa rate (ASR) (P<0.01). Boars were divided into two groups with group 1 (G-I) boars having a higher SCON and SMOT, lower SVOL (sperm volume) and group 2 (G-II) having a lower SCON and SMOT, higher SVOL. The mRNA and protein expression levels were evaluated in reproductive, non-reproductive tissues and spermatozoa from G-I and G-II animals by using quantitative real-time PCR and western blotting. When both reproductive and non-reproductive tissues were examined, highest mRNA was expressed in prostate gland, then in the body of the epididymis, vas deferens and tail of the epididymis. In case of reproductive tissues, CD9 expression was higher in tissues and spermatozoa collected from G-I boars than those collected from G-II boars. The mRNA expression was significantly different (P<0.05) in body of epididymis from G-I and G-II boars. The CD9 protein expression results from western blot were coincided with the results of qRT-PCR. Moreover, CD9 protein localization in Leydig cells, Sertoli cells, epithelial cells and spermatozoa was remarkable which indicated the important role of CD9 in spermatogenesis process. By using mRNA and protein expression profiles, it could be shown that CD9 plays a crucial role during sperm development, especially within the epididymis where the maturation of the sperm, a key process for the sperm quality and motility takes place. These results will improve the understanding of the functions of the CD9 in spermatogenesis within the reproductive tracts and will shed light on CD9 as a candidate gene in the selection of good sperm quality boars.

Transcriptome dynamics and molecular cross-talk between bovine oocyte and its companion cumulus cells

BACKGROUND

The bi-directional communication between the oocyte and its companion cumulus cells (CCs) is crucial for development and functions of both cell types. Transcripts that are exclusively expressed either in oocytes or CCs and molecular mechanisms affected due to removal of the communication axis between the two cell types is not investigated at a larger scale. The main objectives of this study were: 1. To identify transcripts exclusively expressed either in oocyte or CCs and 2. To identify those which are differentially expressed when the oocyte is cultured with or without its companion CCs and vice versa.

RESULTS

We analyzed transcriptome profile of different oocyte and CC samples using Affymetrix GeneChip Bovine Genome array containing 23000 transcripts. Out of 13162 genes detected in germinal vesicle (GV) oocytes and their companion CCs, 1516 and 2727 are exclusively expressed in oocytes and CCs, respectively, while 8919 are expressed in both. Similarly, of 13602 genes detected in metaphase II (MII) oocytes and CCs, 1423 and 3100 are exclusively expressed in oocytes and CCs, respectively, while 9079 are expressed in both. A total of 265 transcripts are differentially expressed between oocytes cultured with (OO+CCs) and without (OO-CCs) CCs, of which 217 and 48 are over expressed in the former and the later groups, respectively. Similarly, 566 transcripts are differentially expressed when CCs mature with (CCs+OO) or without (CCs-OO) their enclosed oocytes. Of these, 320 and 246 are over expressed in CCs+OO and CCs-OO, respectively.While oocyte specific transcripts include those involved in transcription (IRF6, POU5F1, MYF5, MED18), translation (EIF2AK1, EIF4ENIF1) and CCs specific ones include those involved in carbohydrate metabolism (HYAL1, PFKL, PYGL, MPI), protein metabolic processes (IHH, APOA1, PLOD1), steroid biosynthetic process (APOA1, CYP11A1, HSD3B1, HSD3B7). Similarly, while transcripts over expressed in OO+CCs are involved in carbohydrate metabolism (ACO1, 2), molecular transport (GAPDH, GFPT1) and nucleic acid metabolism (CBS, NOS2), those over expressed in CCs+ OO are involved in cellular growth and proliferation (FOS, GADD45A), cell cycle (HAS2, VEGFA), cellular development (AMD1, AURKA, DPP4) and gene expression (FOSB, TGFB2).

CONCLUSION

In conclusion, this study has generated large scale gene expression data from different oocyte and CCs samples that would provide insights into gene functions and interactions within and across different pathways that are involved in the maturation of bovine oocytes. Moreover, the presence or absence of oocyte and CC factors during bovine oocyte maturation can have a profound effect on transcript abundance of each cell types, thereby showing the prevailing molecular cross-talk between oocytes and their corresponding CCs.

Epistatic QTL pairs associated with meat quality and carcass composition traits in a porcine Duroc × Pietrain population

Background

Quantitative trait loci (QTL) analyses in pig have revealed numerous individual QTL affecting growth, carcass composition, reproduction and meat quality, indicating a complex genetic architecture. In general, statistical QTL models consider only additive and dominance effects and identification of epistatic effects in livestock is not yet widespread. The aim of this study was to identify and characterize epistatic effects between common and novel QTL regions for carcass composition and meat quality traits in pig.

Methods

Five hundred and eighty five F₂ pigs from a Duroc × Pietrain resource population were genotyped using 131 genetic markers (microsatellites and SNP) spread over the 18 pig autosomes. Phenotypic information for 26 carcass composition and meat quality traits was available for all F₂ animals. Linkage analysis was performed in a two-step procedure using a maximum likelihood approach implemented in the QxPak program.

Results

A number of interacting QTL was observed for different traits, leading to the identification of a variety of networks among chromosomal regions throughout the porcine genome. We distinguished 17 epistatic QTL pairs for carcass composition and 39 for meat quality traits. These interacting QTL pairs explained up to 8% of the phenotypic variance.

Conclusions

Our findings demonstrate the significance of epistasis in pigs. We have revealed evidence for epistatic relationships between different chromosomal regions, confirmed known QTL loci and connected regions reported in other studies. Considering interactions between loci allowed us to identify several novel QTL and trait-specific relationships of loci within and across chromosomes.

Identification of expression QTL (eQTL) of genes expressed in porcine M. longissimus dorsi and associated with meat quality traits

BACKGROUND

Genetic analysis of transcriptional profiles is a promising approach for identifying and dissecting the genetics of complex traits like meat performance. Accordingly, expression levels obtained by microarray analysis were taken as phenotypes in a linkage analysis to map eQTL. Moreover, expression levels were correlated with traits related to meat quality and principle components with high loadings of these traits. By using an up-to-date annotation and localization of the respective probe-sets, the integration of eQTL mapping data and information of trait correlated expression finally served to point to candidate genes for meat quality traits.

RESULTS

Genome-wide transcriptional profiles of M. longissimus dorsi RNAs samples of 74 F2 animals of a pig resource population revealed 11,457 probe-sets representing genes expressed in the muscle. Linkage analysis of expression levels of these probe-sets provided 9,180 eQTL at the suggestive significance threshold of LOD > 2. We mapped 653 eQTL on the same chromosome as the corresponding gene and these were designated as 'putative cis-eQTL'. In order to link eQTL to the traits of interest, probe-sets were addressed with relative transcript abundances that showed correlation with meat quality traits at p ≤ 0.05. Out of the 653 'putative cis-eQTL', 262 transcripts were correlated with at least one meat quality trait. Furthermore, association of expression levels with composite traits with high loadings for meat quality traits generated by principle component analysis were taken into account leading to a list of 85 genes exhibiting cis-eQTL and trait dependent expression.

CONCLUSION

Holistic expression profiling was integrated with QTL analysis for meat quality traits. Correlations between transcript abundance and meat quality traits, combined with genetic positional information of eQTL allowed us to prioritise candidate genes for further study.

Microbiological and SYBR green real-time PCR detection of major Fusarium head blight pathogens on wheat ears

Fusarium head blight (FHB) caused by several Fusarium species is one of the most serious diseases affecting wheat throughout the world. The efficiency of microbiological assays and real-time PCRto quantify major FHB pathogens in wheat ears after inoculation with F. graminearum, F. culmorum, F. avenaceum and F. poae undergreenhouse and field conditions were evaluated. The frequency of infected kernel, content of fungal biomass, disease severity and kernel weight were determined. To measure the fungal biomass an improved DNA extraction method and a SYBR Green real-time PCR were developed. The SYBR Green real-time PCR proved to be highly specific for individual detection of the species in a matrix including fungal and plant DNA. The effect of Fusarium infection on visible FHB severity, frequency of infected kernels and thousand-kernel mass (TKM) significantly depended on the Fusarium species/isolate. F. graminearum resulted in highest disease level, frequency of infected kernels, content of fungal biomass, and TKM reduction followed by F. culmorum, EF avenaceum and F. poae, respectively. The comparison of frequency and intensity of kernel colonization proved differences in aggressiveness and development of the fungi in the kernels. Only for F. graminearum, the most aggressive isolate, application of microbiological and real-time PCR assays gave similar results. For the other species, the intensity of kernel colonization was lower than expected from the frequency of infection.

Effect of elevated circulating progesterone concentration on bovine blastocyst development and global transcriptome following endoscopic transfer of in vitro produced embryos to the bovine oviduct

Elevated concentrations of circulating progesterone in the immediate postconception period have been associated with an increase in embryonic growth rate, interferon-tau production, and pregnancy rate in cattle and sheep. Much of this effect is likely mediated via downstream effects of progesterone-induced changes in gene expression in the uterine tissues. Using state-of-the-art endoscopic techniques, this study examined the effect of elevated progesterone on the development of in vitro produced bovine zygotes transferred to the oviducts of heifers with high or normal circulating progesterone concentrations and on the transcriptome of blastocysts developing under such conditions. Simmental heifers (n = 34) were synchronized using a controlled internal drug release (CIDR) device for 8 days, with a prostaglandin F(2 alpha) analogue administered 3 days before removal of the CIDR device. Only animals exhibiting a clear standing estrus (Day 0) were used. To produce animals with divergent progesterone concentrations, half of the animals received a progesterone-releasing intravaginal device (PRID) on Day 3 of the estrous cycle; the PRID was left in place until embryo recovery. All animals were sampled for blood daily from Day 0 to Day 7. Cleaved embryos were transferred by endoscopy to the ipsilateral oviduct of each recipient on Day 2 and then recovered by nonsurgically flushing the oviduct and the uterus on Day 7. The number of embryos developing to the blastocyst stage was recorded at recovery and following overnight culture in vitro. Potential effects of elevated progesterone on transcript abundance were examined using the Affymetrix GeneChip Bovine Genome Array. Insertion of a PRID on Day 3 resulted in a significant elevation of progesterone concentration (P < 0.05) from Day 3.5 until Day 6. Elevated progesterone did not affect the proportion of embryos developing to the blastocyst stage. Genomewide gene expression analysis identified 194 differentially expressed genes between embryos collected from heifers with normal or elevated progesterone, and quantitative real-time PCR validation with a subset of selected genes and an independent sample confirmed the microarray results. Interaction network analysis indicated a significant interaction between progesterone-regulated genes in the blastocyst and in the maternal endometrium. These results suggest that elevated concentrations of progesterone do not affect the ability of the early embryo to reach the blastocyst stage in vivo but do result in subtle changes to the transcriptome of the embryo that may be associated with advanced elongation posthatching.

Molecular characterization and methylation study of matrix gla protein in articular cartilage from pig with osteochondrosis

Osteochondrosis (OC) or leg weakness is an economically important disease of young fast growing pigs and is a concern of animal welfare. The etiology and pathogenesis of osteochondrosis is not fully understood yet, but any abnormalities in the formation of hypertrophic chondrocytes and disrupted blood supply to the growth cartilage are very important predisposing factors. Matrix gla protein (MGP) as a potential calcification inhibitor of extracellular matrix might contribute to the development of OC. Molecular characterization, polymorphisms analysis, methylation at promoter region and expression of MGP gene and protein were performed in both healthy and OC cartilage collected from a DurocxPietrain resource population. The porcine MGP gene consists of 4 exons and 3 introns. The full-length MGP cDNA isolated from articular cartilage consists of 606 bp with a 69-bp 5' UTR, a 312-bp open reading frame with a start codon, a 225-bp 3' UTR. Three single-nucleotide polymorphisms (SNP) were detected in the intron 1 (A-115G, C-1073T and C-1135A) and one in the 3'UTR (C-3767T). The relative abundance of MGP mRNA was lower (P<0.05) in OC compared with healthy cartilage. Moreover, the intensity of MGP band was lower (P<0.05) in OC group when quantified by western blot. Furthermore, one CpG region was identified in MGP promoter and DNA methylation of three CG sites were higher in OC compared with normal cartilage. This suggested that the high DNA methylation at specific CG sites in the MGP promoter might be involved in the down regulation of MGP in OC. Immunofluorescence of normal cartilage collected from pigs of different ages revealed that MGP signals were higher in younger pigs and decreased in the older pigs. The MGP protein was expressed more near to the cartilage canals. These results suggest that the MGP gene might be a potential candidate gene for the development of OC in pigs.

Molecular characterization of five porcine candidate genes for drip loss in pork

Drip loss is the loss of fluid from a piece of meat without mechanical force and represents an important meat quality trait. Previous work revealed a quantitative trait locus (QTL) for drip loss in pork in an experimental Duroc x Pietrain (DUPI) F2 family on SSC 5. Based on functional data indicating their possible involvement in water holding capacity and their expression in skeletal muscle, we selected five positional candidates (ACO2, ADSL, CBY1, KCNJ4, PLA2AG6) out of 130 predicted genes in the QTL interval for further analysis. We performed a mutation analysis of all coding exons and discovered 204 polymorphisms. We genotyped 39 single nucleotide polymorphisms (SNPs) in 192 Pietrain pigs with extreme drip loss phenotypes and detected a possible association with drip loss for one non-coding SNP in the ADSL gene (ss107793818, p(raw) = 0.021). Correspondingly, ADSL diplotypes were associated with drip loss and pH1 of M. longissimus dorsi. However, after correction for multiple testing, none of the tested SNPs were significantly associated with drip loss. One possible explanation for these results is that one of the QTL-alleles from the experimental DUPI family may be fixed or nearly fixed in the tested Pietrain population.

Suppression of the transcription factor MSX1 gene delays bovine preimplantation embryo development in vitro

This study was conducted to investigate the effect of suppressing transcription factor geneMSX1on the development ofin vitroproduced bovine oocytes and embryos, and identify its potential target genes regulated by this gene. Injection of long double-stranded RNA (LdsRNA) and small interfering RNA (siRNA) at germinal vesicle stage oocyte reducedMSX1mRNA expression by 73 and 37% respectively at metaphase II stage compared with non-injected controls. Similarly, injection of the same anti-sense oligomers at zygote stage reducedMSX1mRNA expression by 52 and 33% at 8-cell stage compared with non-injected controls. Protein expression was also reduced in LdsRNA- and siRNA-injected groups compared with non-injected controls at both stages. Blastocysts rates were 33, 28, 20 and 18% in non-injected control, scrambled RNA (scRNA), LdsRNA- and siRNA-injected groups respectively. Cleavage rates were also significantly reduced in Smartpool siRNA (SpsiRNA)-injected group (53.76%) compared with scRNA-injected group (57.76%) and non-injected control group (61%). Large-scale gene expression analysis showed that 135 genes were differentially regulated in SpsiRNA-injected group compared with non-injected controls, of which 54 and 81 were down- and up-regulated respectively due to suppression ofMSX1. Additionally, sequence homology mapping and gene enrichment analysis with known human pathway information identified several functional modules that were affected due to suppression ofMSX1. In conclusion, suppression ofMSX1affects oocyte maturation, embryo cleavage rate and the expression of several genes, suggesting its potential role in the development of bovine preimplantation embryos.

Suppression of keratin 18 gene expression in bovine blastocysts by RNA interference

The expression of the cytoskeleton protein Keratin 18 (KRT18) starts at the onset of bovine blastocyst formation. KRT18 is solely expressed in the trophectoderm and can therefore be used as a marker for trophectodermal differentiation. In the present study, the expression of KRT18 was suppressed by RNA interference to probe its functional importance in bovine blastocyst formation. Microinjection of KRT18 double-stranded RNA into the cytoplasm of zygotes resulted in reduced KRT18 mRNA (76% reduction) and protein expression at the blastocyst stage and a lower developmental competence (41% reduction in the percentage of blastocyst formation) compared with non-injected and phosphate-buffered saline (PBS)-injected controls. KRT18 downregulation was associated with reduced mRNA expression of KRT8, the binding partner of KRT18, but had no effect on the expression of KRT19, CDH1 and DSP, other genes involved in intermediate filament and cytoskeleton formation. The results of the present study demonstrated that KRT18 knockdown in preimplantation embryos results in reduced blastocyst formation, but no further morphological aberrations were observed with regard to the biological function of KRT18. These observations could be due to the function of KRT18 being replaced by that of another gene, the surviving blastocysts expressing the minimum level of KRT18 required for normal blastocyst development or the possibility that further aberrations may occur later in development.

Bovine pretransfer endometrium and embryo transcriptome fingerprints as predictors of pregnancy success after embryo transfer

Aberrant gene expression in the uterine endometrium and embryo has been the major causes of pregnancy failure in cattle. However, selecting cows having adequate endometrial receptivity and embryos of better developmental competence based on the gene expression pattern has been a greater challenge. To investigate whether pretransfer endometrial and embryo gene expression pattern has a direct relation with upcoming pregnancy success, we performed a global endometrial and embryo transcriptome analysis using endometrial and embryo biopsy technology and the pregnancy outcome information. For this, endometrial samples were collected from Simmental heifers at day 7 and 14 of the estrous cycle, one cycle prior to embryo transfer. In the next cycle, blastocyst stage embryos were transferred to recipients at day 7 of the estrous cycle after taking 30-40% of the blastocyst as a biopsy for transcriptome analysis. The results revealed that at day 7 of the estrous cycle, the endometrial gene expression pattern of heifers whose pregnancy resulting in calf delivery was significantly different compared with those resulting in no pregnancy. These differences were accompanied by qualitative and quantitative alteration of major biological process and molecular pathways. However, the transcriptome difference was minimal between the two groups of animals at day 14 of the estrous cycle. Similarly, the transcriptome analysis between embryos biopsies that resulted in calf delivery and those resulted in no pregnancy revealed a total of 70 differentially expressed genes. Among these, the transcript levels of 32 genes including SPAG17, PF6, UBE2D3P, DFNB31, AMD1, DTNBP1, and ARL8B were higher in embryo biopsies resulting in calf delivery. Therefore, the present study highlights the potential of pretransfer endometrial and embryo gene expression patterns as predictors of pregnancy success in cattle.

252 FUNCTIONAL CHARACTERIZATION OF miR-130 FAMILY DURING BOVINE PRE-IMPLANTATION EMBRYO DEVELOPMENT

Small noncoding RNA are known to play a regulatory role in various biological processes including development. Here we aimed to investigate the spatiotemporal expression pattern of the miR-130 microRNA family (miR-130a, miR-130b, and miR-301b) throughout the bovine pre-implantation- stage embryos and to experimentally validate the target of miR-130b. For this, triplicate pools of in vitro-produced immature or mature oocytes (n = 100), zygote (n = 100), 2-cell (n = 50), 4-cell (n = 30), 8-cell (n = 30), morula (n = 20), and blastocyst (n = 20) stage embryos were used to profile the 3 miRNA and one of the predicted target gene MSK1 using SYBR green-based real-time PCR system. Furthermore, based on its expression profile result, miR-130b was selected for localization in all stages of embryos using 3′digoxigenin labeled, LNA-modified oligonucleotide probes. Reporter assay was conducted in cultured bovine cumulus cells to validate the target of miR-130b. The predicted MSK1 gene 3′ untranslated region- containing dual-luciferase miRNA target expression vector (pmirGLO; 600 ng), having renilla luciferase as a control reporter (Promega, Madison, WI, USA), was cotransfected with miR-130b precursor (20 pmol) and/or miR-130b inhibitor (20 pmol) using Lipofectamine 2000 (Invitrogen, Carlsbad, CA, USA) in Opti-MEM1 Medium with 4 independent transfections. Cells were lysed 48 h post-transfection, and luciferase assay was performed in luminometer. Normalization of firefly luciferase activity was based on renilla luciferase activity, and data were presented as mean ± SD. The expression profiling result shows that miR-130b was abundant (>8 to 12-fold) at morula and blastocyst stages. This was further validated by in situ localization, where high fluorescent intensity was seen in the same stages. Greater abundance of miR-301b was evident immediately after fertilization at zygote stage, whereas miR-130a was abundant in equal amount from oocyte until 8-cell stage, after which expression reduced at morula and blastocyst stages. Verification of MSK1 as target of miR-130b using MSK1-pmirGLO-vector showed a significant reduction (>45%) in expression of luciferase when cells were cotransfected with miR-130b precursor compared with cotransfection with miR-130b inhibitor (95%) or only MSK1 construct transfection (100%). MSK1, which was validated as target of miR-130b in the current study for the first time, is known to regulate the phosphorylation of CREB and ATF1 and is required for inhibits of Wnt-fi-catenin pathway and cell proliferation in colon cancer cells (Morán OP et al. 2008 J. Cell Biol. 183(4), 697-710). The results from this study evidenced the spatiotemporal expression of members of the miR130 family during bovine embryo development and their potential regulatory mechanism in the expression of developmentally important gene. The overexpression or inhibition of these miRNA in bovine oocytes and embryos might help in fully understanding their specific role in bovine embryogenesis.

254 REGULATORY microRNA IN THE BIDIRECTIONAL COMMUNICATION OF BOVINE OOCYTES AND THE SURROUNDING CUMULUS CELLS

MicroRNA (miRNA) are small molecules (˜22 nucleotide in length) that influence the expression of hundreds of genes for numerous biological processes including development. In this study we aimed to investigate the presence and role of miRNA in the bidirectional communication of oocyte and cumulus cells. For this, triplicate pools each containing 1600 immature and mature oocytes and their corresponding cumulus cells were used for miRNA isolation using miRNeasy® Mini Kit (Qiagen, Hilden, Germany). From each oocyte and cumulus cell group, 50 ng of small RNA was used for reverse transcription using RT2 miRNA First Strand Kit (SABiosciences, Frederick, MD, USA). The resulting small RNA cDNA was used as a template to profile 88 human miRNA related to cell development and differentiation using SYBR green-based real-time PCR system. Data analysis was preformed using the comparative Ct method after normalization using endogenous control RNA (SNORD44, SNORD47, SNORD48, and U6). In addition, miR-205 and miR-210 were used for localization in pre-implantation stages of embryo using 3′digoxigenin labeled, LNA- modified in situ oligonucleotide probes (Exiqon, Vedbaek, Denmark). The result of the PCR array revealed a total of 34 and 49 miRNA to be greatly abundant in immature and mature oocyte, respectively, compared with the corresponding cumulus cells, whereas only 5 and 4 miRNA were enriched in cumulus cells compared with immature and matured oocytes, respectively. Based on expression intensity, 6 oocyte enriched (miR-205, miR-150, miR-96, miR-122, miR-146a, and miR-146b-5p) and 2 cumulus-cell enriched (miR-452 and miR-210) were selected for expression analysis in pre-implantation-stage embryos and in oocyte and cumulus cells matured with or without cumulus and oocyte factors, respectively. All oocyte-specific miRNA were found to be greatly abundant in early stages of embryo development and drop after 4-cells until the blastocyst stage, following a typical maternal transcript profile. Similar results were obtained by localization of miR-205 in pre-implantation-stage embryos, in which signals were greater until the 4-cell stage and reduced thereafter. However, miR-210 and miR-452 showed no defined profile. miR-205, miR-150, miR-122, miR-146a, miR-146b-5p, and miR-452 were found to be abundant at a greater level (P < 0.05) in oocytes matured without cumulus cells compared with those matured in the presence of cumulus cells. The expression of miR-205, miR-150, and miR-122 in cumulus cells was greater in the presence of oocyte cytoplasm during maturation, whereas 16-fold increases in relative abundance of miR-210 were observed in oocyte- optimized cumulus cells. These results evidenced that oocyte and cumulus cells have a distinct set of miRNA, which is dependent on the bidirectional communication of the oocyte and the surrounding cumulus cells. Moreover, maternal miRNA were found to persist until the major genome activation in bovine.

248 DIESTRUS TRANSCRIPTOME DYNAMICS OF BOVINE ENDOMETRIUM IN RELATION TO PREGNANCY SUCCESS AFTER EMBRYO TRANSFER

This experiment aimed to investigate the diestrus transcriptome dynamics of endometrium that resulted in calf delivery or no pregnancy after embryo transfer. Endometrium biopsies were collected from Simmental cyclic heifers at Days 7 and 14 of estrus cycle. On the next cycle, in vivo-produced Day 7 blastocysts were transferred to all animals at Day 7 of estrous cycle. Following pregnancy diagnosis, the endometrial biopsies collected at Day 7 and 14 were categorized based on the pregnancy success. Those endometrial biopsies collected from heifers that subsequently delivered a calf were assigned to the calf-delivery group, and those collected from heifers that did not conceive were assigned to the no-pregnancy group. The endometrial temporal transcriptome profile was compared between Days 7 and 14 in both heifer groups. Total RNA was isolated from each sample in triplicate. Two rounds of RNA amplification were performed using MEGAscript® T7 Kit (Ambion, Inc., Austin, TX, USA) and GeneChip® IVT Labeling Kit (Affymetrix, Inc., Santa Clara, CA, USA), respectively. Following fragmentation, biotin-labeled cRNA samples were hybridized to Affymetrix bovine gene chip array. The microarray data normalization and background correction were performed using GCRMA, and the differentially expressed genes (DEG) (fold change >2,P < 0.05, FDR < 0.3) were identified using LIMMA written on R package integrated with Bioconductor. The result showed that in the calf-delivery group, there were 1867 DEG, among which 1015 and 852 were up- and down-regulated, respectively, in Day 7 compared with Day 14 of the estrous cycle. Some of those genes are believed to be involved in reproductive system development and function (F3, PTGER2, PTGER4, MFGE8, PTGS2, and TDGF1), embryonic development (ALDH1A1,ALDH1A3, FGF2, TGFBR2, PDGFB, and TGFBR2), and nervous system development and function (CYP3A4, CYP3A4, HSD17B4, FOXA2, MET, TDGF, WNT11). The bioinformatic analysis using KEGG revealed that those DEG were classified into several pathways including the MAPK signaling pathway. On the other hand, in the no-pregnancy group, 254 genes were found to be differentially expressed, of which 160 and 94 were up- and down-regulated, respectively, in Day 7 compared with Day 14 of the estrous cycle. Some of these genes were found to be involved in signal transducer activity (AXIN2, AGTR1, MAPK10, NTRK2, TLR2, DMBT1, IL1RN, CDK5, CHRNE), transferase activity (DGKI, TXNDC6, RPS6KA5, RIOK3, MYLK, CDK5, MET, NTRK2), receptor activity (MET,AGTR1, NTRK2, TLR2, DMBT1, CHRNE), regulation of transcription (FOS, ELF1, BHLHB2,ATF3, HOXA11), signal transduction (TLR2, AGTR1, FCNB, DGK, NOTCH2, ADAM9, PLEK), and transcription regulator activity (BHLHB2, FOS, ELF1,ATF3, HOXA11). Those DEG were found to be involved in different pathways including the focal adhesion pathway. In conclusion, the result of the current study revealed a remarkable transcriptome dynamics between Days 7 and 14 of the estrous cycle in cows resulted in calf delivery compared with those that did not support pregnancy.

Depletion of BIRC6 leads to retarded bovine early embryonic development and blastocyst formation in vitro

Baculoviral inhibitors of apoptosis repeat-containing 6 (BIRC6) is believed to inhibit apoptosis by targeting key cell-death proteins. To understand its involvement during bovine preimplantation embryo development, two consecutive experiments were conducted by targeted knockdown of its mRNA and protein using RNA interference. In Experiment 1, the effect of BIRC6 knockdown during the early stages of preimplantation embryo development was assessed by injecting zygotes with long double-stranded RNA (ldsRNA) and short hairpin RNA (shRNA) against BIRC6 mRNA followed by in vitro culturing until 96 h post insemination (hpi). The results showed that in RNA-injected zygote groups, reduced levels of BIRC6 mRNA and protein were accompanied by an increase (P < 0.05) in the proportion of 2- and 4-cell and uncleaved embryos and a corresponding decrease (P < 0.05) in the number of 8-cell embryos. In Experiment 2, the effect of BIRC6 knockdown on blastocyst formation, blastocyst total cell number and the extent of apoptosis was investigated. Consequently, zygotes injected with ldsRNA and shRNA resulted in lower (P < 0.05) blastocyst formation and total blastocyst cell number. Moreover, the apoptotic cell ratio, CASPASE 3 and 7 activity, BAX to BCL-2 ratio and levels of SMAC and CASPASE 9 were higher in blastocysts derived from the ldsRNA and shRNA groups, suggesting increased apoptosis in those blastocysts. The results of this study reveal the importance of BIRC6 expression for embryo survival during bovine preimplantation embryo development. However, whether BIRC6 is essential for implantation and fetal development during bovine pregnancy needs further research.

The noncoding genome: implications for ruminant reproductive biology

Advances in the analyses of human and other higher eukaryotic genomes have disclosed a large fraction of the genetic material (ca 98%) which does not code for proteins. Major portion of this non-coding genome is in fact transcribed into an enormous repertoire of functional non coding RNA molecules (ncRNAs) rather than encoding any proteins. Recent fascinating and fast progress in bioinformatic, high-throughput sequencing and other biochemical approaches have fuelled rapid growth in our appreciation of the tremendous number, diversity and biological importance of these ncRNAs in the hidden layer of gene regulation both at transcriptional and post-transcriptional level. Broadly ncRNAs fall into three size classes namely, 20 nucleotides for the large family of microRNAs (miRNAs), to 25-200 nucleotides for other different families of small RNAs and finally to over thousands of nucleotides for macro ncRNAs involved in eukaryotic gene regulation. Among the ncRNAs that have revolutionized our understanding of eukaryotic gene expression, microRNAs (miRNAs) have recently been emphasized extensively with enormous potential for playing a pivotal role in disease, fertility and development. They are found to be potentially involved in various aspects of physiological regulation of reproductive tissues (testis, ovary, endometrium and oviduct), cells (sperm and oocytes) and embryonic development in addition to other body systems. Here, we review the recent work on miRNAs in details and some other small ncRNAs briefly in animal models focusing on their diverse roles in the physiology of reproductive cells and tissues together with their implications for ruminant reproductive biology.

240 DIFFERENCES IN GLOBAL TRANSCRIPTOME PROFILE OF BOVINE BLASTOCYSTS DERIVED FROM SUPEROVULATED OR SYNCHRONIZED CYCLIC HEIFERS

Estrus synchronization and superovulation are the most widely used procedures in embryo transfer technology. However, changes in the oviduct and uterine environment due to these procedures and the subsequent influence on embryos have not yet been investigated. This study was con- ducted to investigate the effect of oviduct environment of only synchronized or superovulated cyclic heifers on the gene expression profile of blastocysts. Bovine Affymetrix array analysis was performed using 2 groups of blastocysts. The first group was bovine blastocysts produced after superovulation of Simmental heifers (n = 9) using 8 consecutive FSH injections over 4 days in decreasing doses (in total, 300-400 mg of FSH equivalent according to body weight) and flushed at Day 7 by nonsurgical endoscopic method. The second group was bovine blastocysts derived from synchronized Simmental heifers (n = 4) after transfer of 2-cell stage embryos from superovulated donor Simmental heifers (n = 9) by nonsurgical transvaginal endoscopy tubal transfer method. Total RNA was extracted from 3 pools of embryos from each experimental group (6 embryos per pool). A total of 6 biotin-labeled cRNA samples were hybridized on 6 bovine Affymetrix arrays. Data analysis was performed using LIMMA written on R package, which maintained the Bioconductor. Array data analysis revealed a total of 454 transcripts to be differen- tially expressed (P < 0.05, fold change >2) between the 2 groups. Of these, 429 and 25 were up- and down-regulated, respectively, in blastocysts derived from superovulated heifers compared with those derived from synchronized animals. Genes involved in response to stress (HSPA14 and HSPE1), cellular and metabolic processes (CPSF3, ATPIF1, POMP, and MDH2), translation (RPS17, EEF1B2, and EIF4E), and cell commu- nication (FN1, KRT18, and DSG2) were found to be enriched in blastocysts derived from superovulated animals. On the other hand, protein metabolic processes related genes (CLGN) were found to be enriched in blastocysts derived from the synchronized group. The KEGG analysis of the differentially expressed genes showed that the ribosome and oxidative phosphorylation pathways are the dominant pathways and genes involved in these pathways are greatly abundant in the blastocysts derived from superovulated animals. Quantitative real-time PCR has confirmed the transcript abundance of 7 out of 8 genes selected for validation. In conclusion, blastocysts cultured in synchronized animals post 2-cell stage showed significant differences in transcriptome profile compared with their counterparts that remained in superovulated heifers until Day 7. Further functional analysis of some selected candidate genes could give new insights into mechanisms regulating the ability of embryos to survive after transfer.

Identification and characterization of miRNAs expressed in the bovine ovary

Background

MicroRNAs are the major class of gene-regulating molecules playing diverse roles through sequence complementarity to target mRNAs at post-transcriptional level. Tightly regulated expression and interaction of a multitude of genes for ovarian folliculogenesis could be regulated by these miRNAs. Identification of them is the first step towards understanding miRNA-guided gene regulation in different biological functions. Despite increasing efforts in miRNAs identification across various species and diverse tissue types, little is known about bovine ovarian miRNAs. Here, we report the identification and characterization of miRNAs expressed in the bovine ovary through cloning, expression analysis and target prediction.

Results

The miRNA library (5'-independent ligation cloning method), which was constructed from bovine ovary in this study, revealed cloning of 50 known and 24 novel miRNAs. Among all identified miRNAs, 38 were found to be new for bovine and were derived from 43 distinct loci showing characteristic secondary structure. While 22 miRNAs precursor loci were found to be well conserved in more than one species, 16 were found to be bovine specific. Most of the miRNAs were cloned multiple times, in which let-7a, let-7b, let-7c, miR-21, miR-23b, miR-24, miR-27a, miR-126 and miR-143 were cloned 10, 28, 13, 4, 11, 7, 6, 4 and 11 times, respectively. Expression analysis of all new and some annotated miRNAs in different intra-ovarian structures and in other multiple tissues showed that some were present ubiquitously while others were differentially expressed among different tissue types. Bta-miR-29a was localized in the follicular cells at different developmental stages in the cyclic ovary. Bio-informatics prediction, screening and Gene Ontology analysis of miRNAs targets identified several biological processes and pathways underlying the ovarian function.

Conclusion

Results of this study suggest the presence of miRNAs in the bovine ovary, thereby elucidate their potential role in regulating diverse molecular and physiological pathways underlying the ovarian functionality. This information will give insights into bovine ovarian miRNAs, which can be further characterized for their role in follicular development and female fertility as well.

Association of ZYX polymorphisms with carcass and meat quality traits in commercial pigs

Zyxin (ZYX) is one of the proteins in focal adhesions along the actin fibers playing a role in actin organization and signal transduction. By radiation hybrid and genetic mapping we assigned ZYX to porcine chromosome 18 in the area of quantitative traits loci for carcass and meat quality and muscle fiber traits and hence considered ZYX a functional positional candidate gene. Analysis of a newly detected SNPs (c.+279 C>T, c.+399 A>G, c.+522 A>G) in pigs from different commercial breeds (Pietrain [Pi], German Landrace [LR], German Large White x German Landrace [F1] and PiF1) revealed a significant association with carcass traits (including: side- and backfat thickness, loin weight and carcass lean content) and meat quality traits (including: pH, color and drip loss). However, the lack of consistent association across all pig populations in this study indicates that the association of the SNPs may be depending on causal mutations in linkage disequilibrium and/or interactions with other loci.

Gene expression profile of cumulus cells derived from cumulus-oocyte complexes matured either in vivo or in vitro

Although it is well established that maturation conditions have a clear influence on oocyte developmental competence, it is not known whether this could be due to downstream effects of perturbation of the transcript profile of the oocyte's adjacent cumulus cells. Therefore, the aim of the present study was to compare the transcript profiles of cumulus cells derived from cumulus-oocyte complexes (COCs) matured in vitro or in vivo. Using a previously validated combined synchronisation and superstimulation protocol, COCs were recovered from beef heifer ovaries just before the expected time of the LH surge and matured in vitro, while in vivo-matured COCs were recovered just before ovulation (20 h after the LH surge). A custom-made cDNA microarray containing 2278 granulosa/cumulus transcripts was used for target and dye-swap hybridisations. In all, 64 genes were differentially expressed between the two groups. Transcript abundance of key genes associated with cumulus expansion (TNFAIP6) and regulation of oocyte maturation (INHBA and FST) were upregulated in in vivo-derived cumulus cells. However, cumulus cells derived from IVM COCs were enriched with genes involved in response to stress (HSPA5 and HSP90AB1). Quantitative real-time polymerase chain reaction confirmed the array results for eight of 10 genes selected for validation. The data presented here reveal that differences in oocyte developmental capacity after maturation in vitro or in vivo are accompanied by distinct differences in transcript abundance of the surrounding cumulus cells.

Evidence for association of lymphoid enhancer-binding factor-1 (LEF1) with the number of functional and inverted teats in pigs

The lymphoid enhancer-binding factor-1 (LEF1) belongs to a family of regulatory proteins that share homology with the high mobility group protein-1 (HMG1). The LEF1 gene is a mediator in the canonical Wnt-signalling pathway required for morphogenesis of early mammary gland during embryogenesis. Here we describe the molecular characterisation of the porcine LEF1 gene and its association with number of teats and inverted teats in experimental and commercial populations. The 2357-bp cDNA sequence contains an 1197-bp open reading frame encoding a protein of 398 amino acids. The porcine LEF1 protein shares high identity with LEF1 in other mammalian species. The LEF1 gene contains 12 exons and maps to pig chromosome 8 (SSC8). We identified two single nucleotide polymorphisms (SNPs), a T1351C transition and an A1666C transversion, in the 3' end of LEF1. Associations of the SNP A1666C with presence of inverted teats (P<or= 0.01), total number of teats (P <or= 0.01) and total number of inverted teats (P <or= 0.01) were highly significant; SNP T1351C showed near significance with total number of inverted teats (P <or= 0.1) in the experimental DUMI population. SNP T1351C was significantly associated with total number of inverted teats (P= 0.04) and close to significance with affected teats (P = 0.06) in commercial populations. Haplotype analysis confirmed the tendency towards association with affected teats (P = 0.06) in the experimental DUMI population. The function, position, and associations shown here promote LEF1 as a candidate gene for number of teats and in particular for presence and number of inverted teats.

183 EFFECT OF WELL IN WELL CULTURE OF BOVINE EMBRYOS ON GENE EXPRESSION PROFILE

To culture embryos in small groups, the well in well culture system (miniwells harboring 1 single embryo within the well) has been developed previously. In this work, we aimed to examine the effects of the microenvironment provided by well in well culture and embryo density on the relative abundance of transcripts in the resulting embryos. Cumulus–oocyte complexes (COCs) were aspirated from small follicles (2 to 8 mm), and COCs were cultured in 400 μL of modified TCM (TCM-199, Sigma, Taufkirchen, Germany) supplemented with 12% heat-inactivated estrous cow serum and 10 μg mL–1 of FSH (FSH-p, Sheering, Kenilworth, NJ, USA) for 24 h at 39°C in a humidified atmosphere with 5% CO2 in air. Fertilization was performed in Fert-TALP supplemented with 1 μg mL–1 of heparin. Zygotes were allocated randomly in 2 groups, namely: well in well culture (16 miniwells of 0.7 diameter and deepness each containing 1 embryo per well) and group of 16 (group culture of 16 embryos per well). Six pools each containing 20 Day 7 blastocysts derived from the first 2 groups were used to investigate large-scale gene expression analysis using BlueChip cDNA-Array. Three pools each containing 5 blastocysts were used for Array data validation by real-time PCR using primers specific to 5 selected genes (ATP5, PLAC8, KRT8, S100A10, and ZP3). During validation in vivo-derived bovine blastocysts were included to be used as standard. Significance Analysis of Microarray identified 75 transcripts differentially expressed between the 2 groups. Blastocysts derived from well in well culture were found to be enriched with genes regulating different molecular functions including structural constituent of ribosome (RPS29), protein binding (Cul1), calcium ion binding (S100A10, NPTX2), nitric oxide synthase regulator activity (HSPCA), and RNA polymerase II transcription factor activity (UHRF1). However, blastocysts derived from group of 16 culture were found to be enriched with genes involved in oxidoreductase activity (ALOX15, AKR1B), cytochrome-c oxidase activity (COX7A2), hydrogen ion transporting ATP synthase activity (ATP5O), transcription (PTTG1), and cell redox homeostasis (TXN). According to their biological process, genes enriched in blastocysts derived from well in well culture belong to small molecule transport and signal transduction, whereas most downregulated genes have a metabolic function. Comparison of the transcript abundance of the 5 selected genes in the 3 embryo groups showed that the expression of ATP5, PLAC8, and KRT8 in embryos from well in well culture resembles to the relative abundance in blastocyst derived from in vivo culture. However, with respect to the expression of S100A10 and ZP3 genes, blastocysts derived from group culture showed similarity with embryos derived from in vivo. In conclusion, microenvironment affects the gene expression pattern of the resulting embryos.

99 EFFECT OF SUPPRESSION OF BOVINE DNA METHYLTRANSFERASE 1 ON EMBRYONIC DEVELOPMENT AND EXPRESSION OF IMPRINTED GENES

DNA methyltransferase 1 (DNMT1) is believed to be involved in DNA methylation, which is a well-characterized epigenetic modulator shown to have essential functions in germ line and embryonic genome imprinting. This study was conducted to investigate the consequences of suppressing and inhibiting DNMT1 on the development, level of apoptosis, and expression of imprinted genes in pre-implantation bovine embryos. In vitro-produced zygotes were categorized into 4 groups; namely, those injected with Smartpool siRNA (SpsiRNA; Dharmacon Inc., Chicago, IL) (n = 800), 5aza-2′-deoxycytidine (5-AZA; Sigma, St. Louis, MO) (n = 864), nuclease-free water (n = 850), and uninjected control (n = 755). The mRNA expression data were generated using RT-PCR based on the relative standard curve method employing glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as a normalizer. Apoptotic index (API) was calculated by dividing the number of apoptotic cells to total cell number. The proportion of 2-, 4-, 8-cell and 2-, 4-, 8-, and 16-cell embryos was assessed 48 and 72 h, respectively, post-micro injection (pmi), whereas blastocyst rate was assessed at Day 8 pmi. Data on embryonic development and the relative mRNA abundance were analyzed using ANOVA followed by a multiple pair-wise mean comparison using Tukey test. The proportion of 2-, 4-, and 8-cell embryos at 48 h pmi was not significant among treatment groups. However, the proportion of the 8-cell embryos was significantly lower (P < 0.05) in SpsiRNA (16.3 ± 4.5) and 5-AZA injected groups (17.7 ± 4.9) compared with water-injected (26.8 ± 2.9) and uninjected controls (30.7 ± 6.2). The lowest total blastocyst rate (P < 0.05) was observed in the 5-AZA treatment group (16.9 ± 4.9) compared with SpsiRNA (23.4 ± 2.1) and water-injected (24.1 ± 5.3) and uninjected controls (29.4 ± 2.1). Microinjection of SpsiRNA reduced the target mRNA by 80 and 50% in 8-cell and blastocyst stage embryos, respectively, compared with uninjected control, and the protein expression level was also reduced at 8-cell embryos as confirmed by Western blotting. Injection of 5-AZA had no significant effect on mRNA or protein expression. The greatest API (P < 0.05) was found in SpsiRNA (4.2 ± 2.0) and 5-AZA (4.1 ± 1.7) injected groups compared with water-injected (2.8 ± 2.1) and uninjected controls (2.9 ± 2.3). The relative expression study also showed that microinjection of SpsiRNA and 5-AZA increased the expression of IGF2 (by 67 and 55%), IGF2R (29 and 30%), and IGFPB-4 (22 and 24%), respectively, compared with uninjected control, without affecting the expression of both IGF2R and IGFPB-4. In conclusion, suppression of DNMT1 resulted in lower proportion of 8-cell embryos, reduced blastocyst rate, and increased apoptotic index, and affected the expression of some imprinted genes, demonstrating a critical role of this gene in bovine embryonic development.

172 IDENTIFICATION OF MICRORNAS IN BOVINE OVARY

Tightly regulated expression and interaction of a multitude of genes for ovarian folliculogenesis leading to successful oocyte development could be regulated by recently identified new class of small RNAs of ~22 nt (i.e. microRNAs), which are already proved as one of the vital transcriptional regulators in different biological processes including development. But their presence and expression in bovine ovary has not yet been determined. Here, we have attempted to identify miRNAs in bovine ovary by small RNA-cDNA library construction through 5 ligation independent cloning. For this purpose, total RNA enriched with small RNA was isolated from ovary and size fractionated (18 to 24 nt) by denaturing PAGE. Extracted RNA was first 3′ linkered and after template switching by RT, the second 3′ linkering of the first strand cDNA was performed. These linkered small RNA-cDNAs were then amplified with linker-specific primers consisting of BAN I restriction sites, concatemerized by serial ligation, cloned into TOPO TA vector, and transformed into TOP 10 chemically competent cells. After screening, colonies were picked and sequenced. Bioinformatic analysis was done according to the published criteria for the small RNAs. From 233 clones a total of 479 reads were identified. Frequency of sequence length found in the library was 26.8% for ≤18 nt, 55.1% for 19 to 22 nt, and 18.1% for ≥23 nt. The total 479 sequences identified in the library represent 35% miRNAs, 12% mRNA, 12.1% rRNA, 5.6% tRNA, 4.2% repeat associated siRNA, 3.8% non-repeat-associated siRNA, 4% tiny noncoding RNA, 1% small nuclear RNA, and 16% sequences not matched to bovine genome. All 171 miR sequences comprised 79 distinct miRNAs, of which 45 miRNAs already annotated in miRBase for bovine and the other 34 miRNAs are new discoveries. Of the 34 newly identified miRNAs, 12 are described in other species but not yet in bovine. Most of the miRNAs cloned into multiple times, where let-7a cloned for 10, let-7b for 28, let-7c for 13, miR-21 for 4, miR-23b for 11, miR-24 for 7, miR-27a for 6, miR-126 for 4, and miR-143 for 11 times. Based on best hit score, P-value and free energy by online target prediction, some of the bta-miR identified in the library (let-7b, 15b, 18a, 23b, 101, 125b, 126, 140, 145, 199a) are found to target hundreds of genes related to follicular development, ovulation and hormonal regulation. Further functional characterization of some selected miRNAs including expression profiling and in situ localization in follicles of different size and cycles may supplement the results of this study and will enable us to gain insight into their relation to female fertility.

196 EMBRYO BIOPSY TRANSCRIPTOMICS: A POTENTIAL TOOL TO IDENTIFY TRANSCRIPTS DIRECTLY RELATED TO THE ABILITY OF THE EMBRYO TO INDUCE PREGNANCY AFTER TRANSFER

The incidence of pregnancy loss due to embryonic mortality in cattle is one of the major causes of reproductive failure. The early embryonic loss can be due to problems with the embryo itself, the uterine environment, or interactions between the embryo and the uterus. So, this study was conducted to investigate the gene expression profile of bovine embryo biopsies produced in vivo and in vitro that resulted in different pregnancy outcomes. For this, biopsies representing 30 to 40% of the intact in vitro and in vivo blastocysts were taken, and 60 to 70% part was allowed to re-expand prior to transfer to recipients. Based on the pregnancy outcome after transfer, biopsies (n = 10 per pool) were grouped into 3 distinct phenotypes: those that resulted in no pregnancy, those that resulted in resorption, and those that resulted in successful pregnancy and subsequent calf delivery. A bovine cDNA microarray with 2000 clones was used to analyze the gene expression profiles of 3 replicates from each embryo biopsy group. Array data analysis revealed a total of 50 and 52 genes to be differentially expressed between biopsies derived from in vivo blastocysts that resulted in no pregnancy v. calf delivery and resorption v. calf delivery, respectively. Similarly, a total of 52 and 58 transcripts were differentially expressed between biopsies derived from in vitro-produced blastocysts that resulted in no pregnancy v. calf delivery and resorption v. calf delivery, respectively. Quantitative real-time PCR has confirmed the expression profile of 6 selected candidate genes. A distinct set of genes were found to be commonly expressed between in vitro- and in vivo-derived blastocyst biopsies, which ended up with the same pregnancy outcome. Biopsies, which ended up with calf delivery, were found to be enriched with transcripts involved in nucleosome assembly (KRT8), translation (RPLPO), electron transport (COX-2), and placenta specific (PLAC8). On the other hand, transcripts regulating immune response (TNFa), response to stress (HSPD1), and cell adhesion (CD9) were up-regulated in embryos that resulted in no pregnancy or resorption. Differences in transcript abundance of some genes have been seen between biopsies derived from in vitro and in vivo blastocysts. Biopsies from in vivo-derived blastocysts and that ended up with resorption were found to be enriched with transcripts regulating calcium-binding protein (S100A10, S100A14). Transcription factor-related transcripts (CDX2, HOXB7) were up-regulated in vitro-derived blastocyst biopsies that resulted in no pregnancy. In conclusion, the results evidenced that embryos derived from either in vitro or in vivo have more similarities than differences in their transcript abundance with respect to the ability in initiating pregnancy.

114 DEVELOPMENT OF AN OPTIMIZED WELL IN WELL CULTURE SYSTEM: EFFECT OF MINIWELL CALIBER AND CULTURE DROP VOLUME ON DEVELOPMENTAL COMPETENCE OF BOVINE EMBRYOS

To overcome developmental problems due to the scientific need to track single embryos or due to embryo culture in small groups, the Well in Well culture system has been developed previously. Here we aimed to examine the effects of different MiniWell caliber and different embryo densities on developmental rates. Cumulus oocyte complexes (COC) aspirated from small follicles (2–8 mm) were cultured in modified TCM (TCM199, Sigma, Taufkirchen, Germany) supplemented with 12% heat inactivated oestrus cow serum and 10 μg mL–1 FSH (FSH-p, Sheering, Kenilworth, NJ, USA) for 24 h at 39°C in a humidified atmosphere with 5% CO2 in air. Fertilization was performed in Fert-TALP medium. After 20 h coincubation with sperm cells, presumptive zygotes were allocated into MiniWells of different diameter (0.3, 0.4, 0.5, and 0.7 mm) and depth (0.3, 0.5, and 0.7 mm) to investigate the effect of MiniWell diameter and depth on further development of the embryos. To investigate the effect of embryo density we compared the development of zygotes placed in MiniWells with different total volumes of culture medium per well. For all experiments bovine embryos cultured in groups of 16 and groups of 50 served as controls. Developmental rates of in vitro-produced embryos were analysed by chi-square test. Differences of P < 0.05 were considered to be significant. When embryos were cultured in a 4 × 3 factorial design (n = 240 per treatment group in 16 replicates), MiniWell diameter (0.3 mm v. 0.4 mm v. 0.5 mm v. 0.7 mm) significantly affected developmental rates to the blastocyst stage (21.5% v. 26.9% v. 32.5% v. 31.3%, respectively) and MiniWell depth (0.3 mm v. 0.5 mm v. 0.7 mm) influenced development (24.4% v. 27.4% v. 29.3%, respectively). When embryos (n = 160 per treatment group in 10 replicates) were cultured in different total volumes of culture media per Well (0 μL, v. 150 μL v. 500 μL) development of embryos to the blastocyst stage (3.1% v. 13.1% v. 33.1%, respectively) differed significantly. When a total of 240 embryos cultured in 15 replicates in group of 16 were compared with a total of 750 embryos cultured in 15 replicates in group of 50, embryos cultured in group of 16 reached the blastocyst stage at a significantly lower level than zygotes cultured in the group of 50 (22.2% v. 30.3%), whereas zygotes cultured in MiniWells were able to compensate against low embryo densities reaching a blastocyst rate as high as embryos cultured in group of 50 (31.3 v. 30.3%). The best developmental rate of bovine zygotes to the blastocyst stage was observed in MiniWells with a diameter of 0.7 mm and 0.7 mm depth in 500 μL culture medium per well. In conclusion, we successfully optimized the Well in Well culture system by exploring the most suitable MiniWell properties supporting improved developmental rates to the blastoyst stage by compensating against negative effects of low embryo densities allowing to track each individual embryo over the complete culture period.

195 TRANSCRIPTOME PROFILING OF BOVINE ENDOMETRIUM BASED ON THE PREGNANCY OUTCOME AFTER TRANSFER OF IN VIVO-DERIVED EMBRYOS

Transcriptome profiling of pre-transfer cycle endometrium in relation to its ability to sustain the upcoming pregnancy may pave the way to develop or identify molecular markers that can be utilized to detect and select receptive endometrium before embryo transfer. Here, we aim to show differential expression of genes between endometrium biopsies derived from recipients during pre-transfer cycle based on the pregnancy successes after embryo transfer. For this, endometrium biopsies were taken from 56 Simmental cyclic heifers of the same age at day 7 and 14 of the estrous cycle. On the next cycle, in vivo-produced day 7 blastocysts were transferred to all animals at day 7 of the estrous cycle. Pregnancy diagnosis was done at 28, 42, and 56 days of gestation. Thirty-two cows were returned to heat after 21 days, 7 were pregnant until day 42 but no pregnancy after that, and 15 resulted in calf delivery. Subsequently, the endometrium biopsies sampled during the pre-transfer period were categorized based on the pregnancy outcome. Those endometrial biopsies taken at days 7 and 14 during the pre-transferred period from those that resulted in successful calf delivery were named as d7CD and d14CD, respectively, and those endometrial samples collected at days 7 and 14 during pre-transferred period from those groups that resulted in no pregnancy were named as d7NP and d14NP, respectively. Total RNA was extracted from 3 pools of each experimental group in 3 replicates using RNeasy mini kit (Qiagen, Hilden, Germany). A total of 12 biotin-labeled cRNA samples were hybridized on 12 bovine Affymetrix arrays (Affymetrix, Santa Clara, CA, USA) consisting of 24128 probe sets. The microarray data normalization and background correction was performed using guanine cytosine robust multi-array analysis, and the data analysis was performed using LIMMA written on R package, which maintained the bioconductor. The results showed that 1130 transcripts were differentially expressed between d7CD and d7NP, of which 626 and 504 were up- and down-regulated, respectively, in d7CD. Genes that involve in regulation of transcription (PPARA, NR2F1, MYB, MYB, and CHF2) and the collagen families (COL1A1 and COL1A2) were enriched in d7CD. A total of 234 transcripts were differentially expressed between d14CD and d14NP, of which 94 and 140 were up- and down-regulated, respectively, in d14CD compared to d14NP. Transcripts involved in protein amino acid phosphorylation (MA2K6, GATM, AK3L1, and MAPK10) were found to be enriched in d14CD compared to d14NP. In conclusion, pre-transfer endometrium biopsies showed significant differences in transcriptome profile depending on the pregnancy outcome after transfer of in vivo-derived blastocysts and enable to identify transcripts related to pregnancy establishment.

213 POLARIZED LIGHT MICROSCOPY REVEALS AN ASSOCIATION BETWEEN ZONA BIREFRINGENCE INTENSITY AND EMBRYONIC DEVELOPMENT IN BOVINE OOCYTES AND ZYGOTES

To increase the efficiency of human IVP, noninvasive parameters to predict the developmental competence of oocytes and zygotes would be useful for selecting the right embryo to transfer. However, human oocytes and zygotes for experimental studies are rare. Therefore, using a bovine model with a precisely large sample size was the aim of the present study to investigate whether zona birefringence intensity (ZBI), measured by polarization light microscopy of metaphase II (MII) oocytes and zygote-stage embryos, was associated with subsequent development. In this study, ZBI was measured through 2 different parameters, the birefringence peak (PV, average signal strength of polarized light) and the birefringence peak combined with the surface of the signal (CV, average signal strength of polarized light multiplied by the surface of the signal), by using polarized light microscopy and OCTAX polarAIDE-software. Statistical analysis was done by the Tukey-Kramer test using SAS version 9.1. Cumulus–oocyte complexes (COC) were recovered from slaughterhouse ovaries by aspiration. After in vitro maturation, MII oocytes were denuded and activated parthenogenetically (4-min exposure to 5 μm Ionomycin, followed by 3.5 h of incubation in 2 mm 6-DMAP) or fertilized in vitro before denudation. Subsequently, ZBI of MII oocytes (directly after activation) and zygotes (24 h after the beginning of IVF) were measured. To allow tracking of subsequent development, embryos were cultured individually in a well-of-well (WoW) culture system until Day 7 in CR1aa medium (5% CO2, 38.7°C, humidified air). When parthenogenetically activated embryos were cultured (n = 365), 287 (78.6%) cleaved and 115 (31.5%) reached blastocyst stage. The ZBI of MII-activated oocytes did not indicate any differences between those that cleaved and those that did not. On the contrary, we observed significant differences (P < 0.05) for mean values of PV (41.4 v. 43.3) and CV (21.3 v. 22.6) for MII-activated oocytes that subsequently reached the blastocyst stage at Day 7 and those that did not. When IVF zygotes (n = 415, 80.5% cleavage rate and 26.0% blastocyst rate) were analyzed, significantly (P < 0.05) lower mean values of PV (47.1 v. 51.5) and CV (24.7 v. 27.1) were observed for zygotes that cleaved within 48 h compared with zygotes that did not cleave. In addition, mean values of PV (45.5 v. 47.9) and CV (24.3 v. 25.4) for the zygotes that developed to the blastocyst stage at Day 7 were significantly lower in comparison with zygotes that did not develop to that developmental stage. In conclusion, we observed a connection between birefringence intensity at the MII/zygote stage and further development. This may offer benefits for the identification of favorable MII oocytes that could have implications for bovine somatic cell nuclear transfer as well as for human-assisted reproduction technology.

Effect of the microenvironment and embryo density on developmental characteristics and gene expression profile of bovine preimplantative embryos cultured in vitro

The Well of the Well (WOW) system has been developed to culture embryos in small groups or to track the development of single embryos. In the present study, we aimed to examine the effects of the microenvironment provided by the WOW system and embryo density on developmental rates, embryo quality and preimplantative gene expression profile of the resulting embryos. Embryos cultured in a group of 16 reached the blastocyst stage at a significantly lower level than zygotes cultured in a group of 50 (22.2 vs 30.3%), whereas zygotes cultured in WOW were able to compensate against low embryo densities, reaching a blastocyst rate as high as embryos cultured in a group of 50 (31.3 vs 30.3%). Moreover, embryos derived from WOW culture did not differ in terms of differential cell counts and apoptotic cell index compared with controls. The gene expression analysis revealed 62 transcripts to be upregulated and 33 transcripts to be downregulated by WOW culture. Comparing the in vivo derived blastocysts with the blastocysts derived from WOW culture, and group culture, expression of ATP5A1, PLAC8 and KRT8 was more similar to the embryos derived from WOW culture, whereas expression of S100A10 and ZP3 genes was more similar to blastocysts cultured in a group. In conclusion, microenvironment as well as embryo density significantly affected developmental rates. While subsequent blastocysts did not differ in terms of differential cell counts and apoptotic cell index, significant differences were observed in terms of the relative abundance of transcripts in the resulting embryos.

Expression profiling of muscle reveals transcripts differentially expressed in muscle that affect water-holding capacity of pork

To identify biological processes as well as molecular markers for drip loss, a parameter for water holding capacity of meat, the M. longissimus dorsi transcriptomes of six divergent sib pairs were analyzed using Affymetrix Porcine Genome Array. Functional categories of differentially regulated transcripts were determined by single-gene analysis and gene set analysis. The transcripts being up-regulated at high drip loss belong to groups of genes functionally categorized as genes of membrane proteins, signal transduction, cell communication, response to stimulus, and cytoskeleton. Among genes down-regulated with high drip loss, functional groups of oxidoreductase activity, lipid metabolism, and electron transport were identified. Differential regulation of the abundance of transcripts of these biological networks in live muscle affect mortem biochemical processes of meat maturation. Knowledge of this functional link is indicative for the identification of candidate genes for improvement of meat quality.