Temporally differential protein expression of glycolytic and glycogenic enzymes during in vitro preimplantation bovine embryo development

2018 ◽  
Vol 30 (9) ◽  
pp. 1245 ◽  
Author(s):  
Manuel García-Herreros ◽  
Constantine A. Simintiras ◽  
Patrick Lonergan
Keyword(s):  
Embryo Development ◽  
Glucose Transporter ◽  
Developmental Stages ◽  
Glycogen Synthase ◽  
Differentially Expressed ◽  
Bovine Embryo ◽  
Cell Stage ◽  
Glucose Transporter 1 ◽  
Glut 1

Proteomic analyses are useful for understanding the metabolic pathways governing embryo development. This study investigated the presence of enzymes involved in glycolysis and glycogenesis in in vitro-produced bovine embryos at five developmental stages leading up to blastocyst formation. The enzymes examined were: (1) glycolytic: hexokinase-I (HK-I), phosphofructokinase-1 (PFK-1), pyruvate kinase mutase 1/2 (PKM-1/2), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and (2) glycogenic: glycogen synthase kinase-3 isoforms α/ β (GSK-3α/β). Glucose transporter-1 (GLUT-1) was also analysed. The developmental stages examined were: (1) 2–4-cell, (2) 5–8-cell, (3) 16-cell, (4) morula and (5) expanded blastocyst. The enzymes HK-I, PFK-1, PKM-1/2, GAPDH and GLUT-1 were differentially expressed throughout all stages (P < 0.05). GSK-3α and β were also differentially expressed from the 2–4-cell to the expanded blastocyst stage (P < 0.05) and GLUT-1 was identified throughout. The general trend was that the abundance of PFK1, GAPDH and PKM-1/2 decreased whereas HK-I, phospho-GSK3α (P-GSK3α) and P-GSK3β levels increased as the embryo advanced. In contrast, GLUT-1 expression peaked at the 16-cell stage. These data combined suggest that in vitro bovine embryo metabolism switches from being glycolytic-centric to glycogenic-centric around the 16-cell stage, the developmental window also characterised by embryonic genome activation.

scholarly journals Identification and regulation of glycogen synthase kinase-3 during bovine embryo development

Reproduction ◽  
2010 ◽  
Vol 140 (1) ◽  
pp. 83-92 ◽  
Author(s):  
I M Aparicio ◽  
M Garcia-Herreros ◽  
T Fair ◽  
P Lonergan
Keyword(s):  
Embryo Development ◽  
Developmental Stages ◽  
Glycogen Synthase ◽  
Specific Inhibitor ◽  
Blastocyst Stage ◽  
Serine Phosphorylation ◽  
Glycogen Synthase Kinase ◽  
Bovine Embryo ◽  
Bovine Embryos ◽  
Cell Stage

The aim of this study was to examine the presence and regulation of glycogen synthase kinase-3α (GSK3A) and GSK-3β (GSK3B) in bovine embryos and their possible roles in embryo development. Our results show that GSK3A and GSK3B are present in bovine embryos at the two-cell stage to the hatched blastocyst stage. Bovine embryo development was associated with an increase in the phosphorylation of both isoforms, being statistically significant at blastocyst and hatched blastocyst stages, compared with earlier stages. Inhibition of GSK3 with CT99021 (3 μM) resulted in a significant increase in the percentage and quality of blastocysts, while inhibition of GSK3 with lithium chloride (LiCl; 20 mM) significantly reduced at the proportion of eight-cell embryos on day 3 and inhibited blastocyst formation. The use of LY294002 (10 μM), a specific inhibitor of phosphatidylinositol-3 kinase, also produced a significant decrease in embryo development. In addition, treatment with LiCl and LY294002 produced a significant decrease in the serine phosphorylation of both isoforms of GSK3. Finally, CT99021 and LiCl reduced the phosphorylation of β-catenin on Ser45 in two-cell embryos, while LY294002 increased it. Despite the fact that LiCl inhibited GSK3 activity, as demonstrated by β-catenin phosphorylation, its effects on the bovine embryo could be mediated through other signaling pathways leading finally to a decrease in the phosphorylation of GSK3 and a reduction in embryo development. Therefore, in conclusion, GSK3A/B serine phosphorylation was positively correlated with embryo development, indicating the importance of an accurate regulation of GSK3 activity during developmental stages to achieve normal bovine embryo development.

Differential glycolytic and glycogenogenic transduction pathways in male and female bovine embryos produced in vitro

2012 ◽  
Vol 24 (2) ◽  
pp. 344 ◽  
Author(s):  
M. Garcia-Herreros ◽  
I. M. Aparicio ◽  
D. Rath ◽  
T. Fair ◽  
P. Lonergan
Keyword(s):  
Glucose Metabolism ◽  
Protein Expression ◽  
Glucose Uptake ◽  
Glucose Transporter ◽  
Glycogen Synthase ◽  
Bovine Embryos ◽  
High Concentration ◽  
Glucose Transporter 1 ◽  
Male And Female ◽  
Glut 1

Previous studies have shown that developmental kinetic rates following IVF are lower in female than in male blastocysts and that this may be related to differences in glucose metabolism. In addition, an inhibition of phosphatidylinositol 3-kinase (PI3-K) inhibits glucose uptake in murine blastocysts. Therefore, the aim of this study was to identify and compare the expression of proteins involved in glucose metabolism (hexokinase-I, HK-I; phosphofructokinase-1, PFK-1; pyruvate kinase1/2, PK1/2; glyceraldehyde-3-phosphate dehydrogenase, GAPDH; glucose transporter-1, GLUT-1; and glycogen synthase kinase-3, GSK-3) in male and female bovine blastocysts to determine whether PI3-K has a role in the regulation of the expression of these proteins. Hexokinase-I, PFK-1, PK1/2, GAPDH and GLUT-1 were present in bovine embryos. Protein expression of these proteins and GSK-3 was significantly higher in male compared with female blastocysts. Inhibition of PI3-K with LY294002 significantly decreased the expression of HK-I, PFK-1, GAPDH, GSK-3 A/B and GLUT-1. Results showed that the expression of glycolytic proteins HK-I, PFK-1, GAPDH and PK1/2, and the transporters GLUT-1 and GSK-3 is regulated by PI3-K in bovine blastocysts. Moreover, the differential protein expression observed between male and female blastocysts might explain the faster developmental kinetics seen in males, as the expression of main proteins involved in glycolysis and glycogenogenesis was significantly higher in male than female bovine embryos and also could explain the sensitivity of male embryos to a high concentration of glucose, as a positive correlation between GLUT-1 expression and glucose uptake in embryos has been demonstrated.

Quantitative expression analysis of blastocyst-derived gene transcripts in preimplantation developmental stages of in vitro-produced bovine embryos using real-time polymerase chain reaction technology

2004 ◽  
Vol 16 (8) ◽  
pp. 753 ◽  
Author(s):  
Nermin El-Halawany ◽  
Siriluck Ponsuksili ◽  
Klaus Wimmers ◽  
Markus Gilles ◽  
Dawit Tesfaye ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Expression Pattern ◽  
Embryo Development ◽  
Developmental Stages ◽  
Bovine Embryo ◽  
Chain Reaction ◽  
Quantitative Expression ◽  
Polymerase Chain

The main objective of the present study was to analyse the quantitative expression pattern of genes from a subtracted blastocyst transcriptome throughout the preimplantation developmental stages of in vitro-produced bovine oocytes and embryos. For this purpose, Day 5 morula (M) cDNAs were subtracted from Day 7 blastocyst (B) cDNAs (B–M) and used to establish a B–M subtracted cDNA library, as reported previously. From the total generated clones, 19 were analysed quantitatively. The mRNA samples isolated from pools of immature oocytes (n = 150), mature oocytes (n = 150) and two-cell (n = 80), four-cell (n = 40), eight-cell (n = 20), morula (n = 6) and blastocyst (n = 3) embryos were reverse transcribed and subjected to real-time polymerase chain reaction (PCR) using sequence-specific primers and SYBR green as the DNA dye. A relative standard curve method was used to analyse the real-time data taking the morula stage as a calibrator. Applying suppression subtractive hybridisation (SSH), a total of 71 clones, which represent 33 different expressed sequence tags, were generated and available for analysis. Most transcripts were analysed for the first time in bovine embryogenesis. The real-time PCR has validated the results of SSH positively for 84% (16/19) of transcripts, whereas 16% (3/19) showed deviation in the expression pattern from the one seen during SSH. Several transcript-specific expression patterns were observed for genes that play decisive roles in bovine embryogenesis. In addition to identification, accurately quantifying the expression profiles of transcripts during development will pave the way towards understanding the molecular mechanisms of embryogenesis and their potential role in early embryo development. Most importantly, the present study has contributed to the enrichment of bovine embryo gene collection by generating new transcripts involved in bovine embryo development.

103 TRANSDUCTION PATHWAYS RELATED TO GLUCOSE METABOLISM IN MALE AND FEMALE BOVINE EMBRYOS PRODUCED IN VITRO

2011 ◽  
Vol 23 (1) ◽  
pp. 157
Author(s):  
M. Garcia-Herreros ◽  
I. M. Aparicio ◽  
D. Rath ◽  
T. Fair ◽  
P. Lonergan
Keyword(s):  
Glucose Metabolism ◽  
Protein Expression ◽  
Sodium Dodecyl ◽  
Bovine Embryo ◽  
Bovine Embryos ◽  
Glucose Transporter 1 ◽  
Male And Female ◽  
Glut 1 ◽  
Kinetic Rates

Glucose metabolism plays an important role in energy balance control in mammalian cells and has been widely used as an indicator of embryo developmental competence. Previous studies have shown that developmental kinetic rates following IVF are lower in female than in male blastocysts, which may be related to differences in glucose consumption and metabolism. In addition, we have demonstrated that inhibition of phosphatidylinositol 3-kinase (PI3-K) with a structurally unrelated inhibitor, LY294002, suggests a negative role for PI3-K in the regulation of bovine embryo development (Aparicio et al. 2010 Reproduction 140, 83–92). The aim of this study was to determine whether PI3-K has a role in the regulation of glucose metabolism in Day 7 bovine blastocysts and to study the possible differential protein expression involved in glucose metabolism [hexokinase-I (HK-I), phosphofructokinase-1 (PFK-1), pyruvate kinase1/2 (PMK1/2), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), lactate dehydrogenase A/C (LDHA/C), glucose transporter-1 (GLUT-1) and glycogen synthase kinase-3 (GSK-3A/B)] between in vitro produced male and female embryos derived from IVF with either X- or Y-sorted semen. Day 7 blastocysts derived from unsorted semen (n = 25 blastocysts per group) were incubated up to 12 h in SOF culture medium in the presence or absence of LY294002 (10 μM) and stored. Similarly, male and female Day 7 blastocysts derived from sorted semen were collected apart and stored at –80°C until proteomic analysis (Western blot analysis of proteins separated by sodium dodecyl sulfate-polyacylamide gel electrophoresis). Inhibition of PI3K significantly decreased HK-I (P < 0.01), PFK-1 (P < 0.001), GAPDH (P < 0.05), GSK-3A/B (P < 0.001), and GLUT-1 (P < 0.01) protein levels. Interestingly, protein expression of HK-1 (P < 0.001), PFK-1 (P < 0.01), PMK1/2 (P < 0.05), GAPDH (P < 0.01), and GLUT-1 (P < 0.001) was significantly higher in male compared with female blastocysts. The significant increase in the phosphorylated forms (Ser21 and Ser9) of both isoforms (GSK-3A/B) in male compared with female embryos is indicative of a higher inactivation of GSK-3A/B in males (P < 0.001). The presence of LDHA/C activity was not detected in any blastocyst group, irrespective of the gender or treatment studied. In conclusion, our data suggest that PI3K plays a major role in the regulation of glucose metabolism in bovine embryos, because pretreatment with LY294002 significantly modified the protein expression of HK-I, PFK-1, GAPDH, GSK- 3A/B, and GLUT-1, and underline the possibility of modulating glucose metabolism via the PI3K cellular pathway. The differential glycolytic metabolism between male and female blastocysts might explain the higher developmental kinetic rates in males described by other authors, because the expression of proteins involved in glycolysis and glycogenogenesis was significantly higher in male than in female in vitro-produced bovine embryos.

131 GENE SILENCING IN BOVINE ZYGOTES: SIRNA TRANSFECTION v. MICROINJECTION

2010 ◽  
Vol 22 (1) ◽  
pp. 224 ◽  
Author(s):  
C. M. O'Meara ◽  
J. D. Murray ◽  
J. F. Roche ◽  
S. Mamo ◽  
E. Gallagher ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Embryo Development ◽  
Relative Abundance ◽  
Gene Function ◽  
Developmental Stages ◽  
Analysis Data ◽  
Blastocyst Stage ◽  
Cell Stage ◽  
E Cadherin

Ribonucleic acid interference (RNAi) has become an effective tool for studying gene function in a variety of cells. The objective of this study was to compare the efficiency of gene silencing when siRNA were introduced into bovine zygotes by microinjection (as done previously; Tesfaye D et al. 2007 Mol. Reprod. Dev. 74, 978-988) v. a novel method of transfection in terms of gene knockdown and embryo development. For microin-jection, in vitro-produced bovine zygotes (16 h post insemination) were randomly assigned to 1 of 3 groups over 2 experiments. In Experiment 1, E-cadherin siRNA was injected at 100 μM (n = 168) and compared with PBS-injected (n = 180) and noninjected controls (n = 152). In Experiment 2, E-cadherin siRNA was injected at 375 μM (n = 154) and compared with PBS-injected (n = 136) and noninjected controls (n = 151). Embryos were subsequently cultured in vitro until Day 7 (day of IVF = Day 0). For transfection, the zona pellucida was removed from in vitro-produced zygotes. Zona-free zygotes were randomly assigned to 1 of 4 groups (i) GAPDH (n = 67), (ii) scrambled (n = 66), (iii) E-cadherin (n = 69) siRNA treatments at 100 nM or (iv) nontransfected controls (n = 66). Zygotes were incubated in transfection medium with siRNA for 1 h at 39°C, cultured individually in the well-of-the-well system to Day 7. The proportion of zygotes undergoing cleavage and developing to the blastocyst stage was recorded, and Day 7 embryos were frozen individually for mRNA analysis. Data for mRNA expression were fitted to a general linear model, and developmental stages were tested using ANOVA. Microinjection of 100 μM E-cadherin siRNA had no effect on phenotype (P > 0.05). Injection of PBS or 375 μM E-cadherin siRNA resulted in a decrease in the number of embryos reaching the 8-cell stage (51.5%, 45.5%, and 62.9%, respectively) and blastocyst stage (39.0%, 32.5%, and 45%, respectively) compared with noninjected controls (P < 0.05). The mRNA abundance of the target gene was suppressed by 36 and 46% when siRNA targeting E-cadherin was injected at 100 μM and 375 μM compared with control and PBS-injected groups (P < 0.05). Transfection with E-cadherin siRNA decreased development of 8-cell embryos (20.3 v. 53.0%, respectively) and blastocysts (7.2 v. 18.2%, respectively) compared with controls (P < 0.05). The mRNA relative abundance was not different between controls (nontransfected, or transfected with GAPDH or scrambled siRNA). However, transfection of zygotes with 100nM E-cadherin siRNA led to a 70% reduction in E-cadherin mRNA relative abundance in Day 7 blastocysts compared with controls (P < 0.05). Zona removal and transfection resulted in decreased embryo development compared with microinjection (P < 0.05). However, transfection yielded more efficient gene silencing of E-cadherin mRNA with reduced embryo development compared with microinjection. This technique of gene silencing could improve the efficiency of gene function studies in early bovine embryogenesis. Supported by Science Foundation Ireland.

De novo transcription of thyroid hormone receptors is essential for early bovine embryo development in vitro

2018 ◽  
Vol 30 (5) ◽  
pp. 779 ◽  
Author(s):  
N.-Y. Rho ◽  
F. A. Ashkar ◽  
T. Revay ◽  
P. Madan ◽  
G.-J. Rho ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Embryo Development ◽  
De Novo ◽  
Preimplantation Embryos ◽  
Embryo Morphology ◽  
Bovine Embryo ◽  
Cell Stage ◽  
Protein Levels ◽  
Development In Vitro

Thyroid hormone receptor (THR) α and THRβ mediate the genomic action of thyroid hormones (THs) that affect bovine embryo development. However, little is known about THRs in the preimplantation embryo. The aim of the present study was to investigate the importance of THRs in in vitro preimplantation bovine embryos. THR transcripts and protein levels were detected in developing preimplantation embryos up to the blastocyst stage. Embryonic transcription of THRs was inhibited by α-amanitin supplementation, and both maternal and embryonic transcription were knocked down by short interference (si) RNA microinjection. In the control group, mRNA and protein levels of THRs increased after fertilisation. In contrast, in both the transcription inhibition and knockdown groups there were significant (P < 0.05) decreases in mRNA expression of THRs from the 2-cell stage onwards. However, protein levels of THRs were not altered at 2-cell stage, although they did exhibit a significant (P < 0.05) decrease from the 4-cell stage. Moreover, inhibition of de novo transcripts of THRs using siRNA led to a significant (P < 0.01) decrease in the developmental rate and cell number, as well as inducing a change in embryo morphology. In conclusion, THRs are transcribed soon after fertilisation, before major activation of the embryonic genome, and they are essential for bovine embryo development in vitro.

scholarly journals Temporal expression of factors involved in chromatin remodeling and in gene regulation during early bovine in vitro embryo development

Reproduction ◽  
2007 ◽  
Vol 133 (3) ◽  
pp. 597-608 ◽  
Author(s):  
Serge McGraw ◽  
Christian Vigneault ◽  
Marc-André Sirard
Keyword(s):  
Embryo Development ◽  
Developmental Stages ◽  
Epigenetic Modification ◽  
Chromatin Modification ◽  
Bovine Embryo ◽  
Mrna Levels ◽  
Temporal Expression ◽  
Regulate Gene Expression ◽  
Preimplantation Embryo Development

Distinct epigenetic modification events regulate gene expression and chromatin structure during the period between the immature oocyte and the blastocyst. Throughout this developmental period, important methylation fluctuations occur on genomic DNA and histones. Finding single orcombinations offactors, which are at work during this period is essential to understand the entire epigenetic process. With this in mind, we assessed the precise temporal expression profile, during preimplantation embryo development, of 15 key regulators involved in RNA, DNA or histone methylation, chromatin modification or silencing and transcription regulation. To achieve this, real-time RT-PCR was used to quantify the mRNA levels of ATF7IP, DMAP1, EHMT1, EHMT2, HELLS, JARID1A, JARID1B, JMJD1A, JMJD2A, LSD1, MeCP2, METTL3, PRMT2, PRMT5 and RCOR2, in the oocyte and throughout in vitro bovine embryo development. Our results demonstrate that all the 15 key regulators were present to different degrees in the developmental stages tested, and they can be divided into three different groups depending on their respective mRNA profile.

Linoleic (LA) and linolenic (ALA) acid concentrations in follicular fluid of prepubertal goats and their effect on oocyte in vitro maturation and embryo development

2018 ◽  
Vol 30 (2) ◽  
pp. 286 ◽  
Author(s):  
Montserrat Roura ◽  
María G. Catalá ◽  
Sandra Soto-Heras ◽  
Sondes Hammami ◽  
Dolors Izquierdo ◽  
...  
Keyword(s):  
Embryo Development ◽  
Follicular Fluid ◽  
Dna Methyltransferase ◽  
Glucose Transporter ◽  
Mitochondrial Activity ◽  
Glucose Transporter 1 ◽  
Treatment Groups ◽  
Atp Concentration ◽  
Follicle Size

In this study we assessed the concentration of linoleic acid (LA) and linolenic acid (ALA) in follicular fluid of prepubertal goats according to follicle size (<3 mm or ≥3 mm) by gas chromatography and tested the addition of different LA and ALA (LA : ALA) concentration ratios (50 : 50, 100 : 50 and 200 : 50 µM) to the IVM medium on embryo development, mitochondrial activity, ATP concentration and relative gene expression (RPL19, ribosomal protein L19; SLC2A1, facilitated glucose transporter 1; ATF4, activating transcription factor 4; GPX1, glutathione peroxidase 1; HSPA5, heat-shock protein family A 70 kDa; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; DNMT1, DNA methyltransferase 1; GCLC, glutamate–cysteine ligase catalytic subunit; SOD1, superoxide dismutase 1). Oocytes were in vitro matured, fertilised or parthenogenetically activated and zygotes were cultured following conventional protocols. LA concentration ranged from 247 to 319 µM and ALA concentration from 8.39 to 41.19 µM without any effect of follicle size. Blastocyst production from the different groups was: control FCS (22.33%) and BSA (19.63%), treatments 50 : 50 (22.58%), 100 : 50 (21.01%) and 200 : 50 (9.60%). Oocytes from the 200 : 50 group presented higher polyspermy and mitochondrial activity compared with controls and the rest of the treatment groups. No differences were observed in ATP concentration or relative expression of the genes measured between treatment groups. In conclusion, the low number of blastocysts obtained in the 200 : 50 group was caused by a high number of polyspermic zygotes, which could suggest that high LA concentration impairs oocyte membranes.

173 THE EFFECT OF AMINO ACIDS AND HYALURONAN ON BOVINE EMBRYO IN VITRO DEVELOPMENT AND GENE EXPRESSION PATTERN

2006 ◽  
Vol 18 (2) ◽  
pp. 194 ◽  
Author(s):  
A. T. Palasz ◽  
J. Beltrán Breña ◽  
P. De la Fuente ◽  
M. F. Martinez ◽  
A. Gutiérrez-Adán
Keyword(s):  
Gene Expression ◽  
Amino Acids ◽  
Embryo Development ◽  
Control Group ◽  
Bovine Embryo ◽  
In Vitro Development ◽  
Glut 1 ◽  
Vitro Development ◽  
And Control

We have previously shown that bovine embryos cultured in SOFaa (BME + MEM amino acids) culture medium with hyaluronan (HA) + BSA are of better quality (Guti�rrez-Ad�n et al. 2005 Reprod. Fertil. Dev. 17, 219). Our objective was to examine the effect of essential (BME) or non-essential (MEM) amino acids with or without HA (MAP-5; Bioniche, Inc., Belleville, Ontario, Canada) on bovine embryo in vitro development and mRNA transcription of five developmentally important genes; apoptosis (Bax), growth factor (IGF-II), glucose (Glut-1) and fructose (Glut-5) transport and metabolism, and cell to cell adhesion (Cx-43). A total of 1474 presumptive zygotes (5 replicates) were initially cultured in 40 �L drops in the following groups: Group 1, control, SOFaa; Group 2, SOF-1 (MEM only); and Group 3, SOF-2 (BME only). On Day 4 (~96 h post-insemination (pi) the number of zygotes that had developed to d8 cells was recorded and 10 �L of SOF-1 and SOF-2, each with 2.5 mg/mL HA, was added to half of the embryos from Groups 2 and 3, respectively; the other half of Groups 2 and 3 and control group received 10 �L of corresponding medium without HA. Embryos were cultured under paraffin oil at 39�C and 5% CO2 in humidified air. Cleavage rates were recorded on Day 2 and the number of blastocysts on Days 7, 8, and 9. Five blastocysts from each replicate from each treatment were frozen for determination of gene expression patterns later. Cleavage rates and embryo development 96 h pi were compared among groups by chi-square analysis. The effects of HA and medium on blastocyst rates were analyzed by logistic regression and the data on mRNA expression by one-way repeated-measures ANOVA. Cleavage rates were 81.1% in SOFaa and 79.3% in SOF-1 (P = 0.48) and different from those in the SOF-2 group (72.4%; P < 0.02). The proportion of embryos that developed to d8 cells at Day 4 was higher in the control (46.7%) and SOF-1 (46.8%) groups than in the SOF-2 group (32.6%). The number of blastocysts that developed in SOFaa (37.0%), SOF-1 (37.7%), and SOF-1 + HA (37.8%) were higher (P < 0.001) than those in SOF-2 (19.6%) and SOF-2 + HA (21.8%). The level of expression of Glut-5 was not different among the groups. However, SOF-2 was the only group that had significantly lower expression of Glut-5, Igf II, and Cx43, and higher expression of BAX (P < 0.05) as compared to the control group and the SOF-1 groups with or without HA. Addition of HA to SOF-2 medium increased expression of Glut-1 and Igf II and decreased expression of BAX as compared to the SOF-1 only and control groups and the SOF-2 groups with or without HA (P < 0.05). The level of expression of Cx43 was higher in the control than in four remaining groups, and lower in the SOF-2 than in the SOF-1 group (P < 0.05). Addition of HA increased expression of Cx43 in both SOF-1 and SOF-2 groups but this level of expression was lower than in the control group; the level in the SOF-2 + HA group was lower (P < 0.05) than in the SOF-1 + HA group. We conclude that, within our protocol, MEM amino acids only stimulate embryo development to the blastocyst stage and the addition of HA to the SOF-MEM and SOF-BME media on Day 4 of culture improved embryo quality.

194 EXPRESSION OF STANNIOCALCIN FAMILY GENES DURING PREIMPLANTATION STAGE BOVINE EMBRYO DEVELOPMENT

2011 ◽  
Vol 23 (1) ◽  
pp. 197
Author(s):  
S. Mamo ◽  
A. Al Naib ◽  
L. O'Hara ◽  
T. Fair ◽  
P. Lonergan
Keyword(s):  
Embryo Development ◽  
Reference Genes ◽  
Sequence Similarity ◽  
Calf Serum ◽  
Transcript Abundance ◽  
Bovine Embryo ◽  
Cell Stage ◽  
Preimplantation Stage ◽  
Relative Standard

Stanniocalcins (STC) are a small family of secreted homodimeric glycoprotein hormones consisting of STC1 and STC2. A previous study in Drosophila (Tolias and Stroumbakis 1998 Dev. Genes Evol. 208, 274–282) indicated that maternally derived STC is required during embryogenesis. However, little information is available for mammalian embryos. The aim of this study was to examine the expression of STC and assess their roles during the preimplantation stage of bovine embryo development. Immature cumulus–oocyte complexes were aspirated from follicles of bovine ovaries collected at a local abattoir and matured in vitro for 24 h at 39°C under an atmosphere of 5% CO2 in air with maximum humidity in TCM-199 supplemented with 10% (vol/vol) fetal calf serum and 10 ng mL–1 of epidermal growth factor. Matured cumulus–oocyte complexes were inseminated with fertile bull semen (Day 0). Embryos were cultured in vitro, and subsequently, 4 pools of 10 embryos each at the zygote, 2-cell, 4-cell, 8-cell, 16-cell, morula, and blastocyst stages were collected from 4 different replicate cultures and stored at –80°C until analysis. Total RNA was isolated using an RNeasy Micro Kit and a random primer was used during cDNA synthesis. The expression of STC1, STC2, and reference genes (YWHAZ, PPIA, SDHA) was examined. Quantitative real-time PCR was used to compare transcript abundance, and data were normalized to the geometric averages of the reference genes. The expression levels were analysed using the relative standard curve method, and means were compared using Student’s t-test. Despite being members of the same family and having large sequence similarity, the expression of each gene was unique and stage dependent during embryo development. Expression of STC1 was detected in all the stages examined. Expression was transiently reduced at the 2-cell stage, with no significant change until the 8-cell stage but with a slight increase at the 16-cell stage. In contrast, STC2 was barely detectable before the 8-cell stage. Expression at the 8- and 16-cell stages was significantly (P < 0.0001) higher compared with all other stages, with a peak at the 16-cell stage. This significantly higher expression pattern of STC2 during the critical stages of maternal to zygotic control of development may suggest an important role during this critical period of embryo development. Supported by Science Foundation Ireland (07/SRC/B1156).

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