Project description:In order to study early developmental events in the mammalian embryo it is often desirable to be able to impair expression of specific genes. While DNA and RNA methods are routine, protein methods are still at the very beginning. When a specific antibody is supplied to mouse oocytes expressing the ubiquitin-protein ligase TRIM21, a ternary complex forms with the target protein, leading to its rapid and acute degradation - hence the name 'Trim-away' (PMID 29153837). However, there are many unknowns in this new endeavour. First and foremost, the extent to which endogenous proteins can be depleted depends on their amount, in relation to the amount of exogenous antibody, which is limited by the microinjection procedure. Secondly, the depletion of the protein must be sustained over days. Using the iBAQ algorithm we show that proteins found in preimplantation mouse embryos range from 3,5E-10 to 2,6E-02 picomoles. These amounts are tractable with our microinjection method, which supplies up to 100 picoliters and up to 6,7E-4 picomoles antibody before incurring in toxic effects on mouse development. Building on these data, we demonstrate the feasibility of protein knock-down for a gene which is essential in the preimplantation mouse embryo, namely TEAD4 (TEA domain family member 4). Protein knock-down persists for sufficient time to result in a phenotype which is entirely consistent with that of the null mutation (Tead4 -/-) and of the RNA interference, namely: significantly reduced mRNA expression of TEAD4 target genes Cdx2 and Gata3, and embryo’s inability to implant. We conclude that for a time window of 3-4 days of preimplantation development the protein depletion method can be a valid alternative to DNA and RNA methods. After in vivo fertilization and short culture in KSOM(aa) medium, pronuclear-stage oocytes (B6C3F1 x CD1) were microinjected with Trim21 mRNA and dextran beads as tracer (named 'group 4'), or Trim21 mRNA, dextran beads and anti-GFP antibody (named 'group 5'), or Trim21 mRNA, dextran beads and anti-TEAD4 antibody (named 'group 6'), two replicates each ('a' and 'b'). On day 4 after microinjection, the most advanced embryos were examined for phenotype or lysed for transcriptome analysis. TEAD4-depleted embryos formed only 30% blastocysts and these were not able to implant in the outgrowth assay, in contrast to the almost full rates of the embryos injected with Trim21 mRNA or Trim21 mRNA + anti-GFP antibody. Transcriptome analysis revealed that the TEAD4 target genes Cdx2 and Gata3 are significantly reduced in the embryos that received the anti-TEAD4 antibody compared to the embryos that received Trim21 mRNA only, while the embryos that received anti-GFP antibody were much similar to those that received Trim21 mRNA only.
Project description:Mutation studies always defined the functions of the zona pellucida (ZP) as extracellular, namely: to encase the oocytes in ovarian follicles, to ensure species-specific sperm binding, and to dampen shear stress on the embryo surface. Therefore, mutations in the three ZP mouse genes ZP1, ZP2 or ZP3 cause primary infertility due to empty follicles, polyspermic fertilization or harmful contact between embryos and oviductal epithelium. However, the concepti of ZP2-null and ZP3-null oocytes were still unviable also when the defects were obviated by monospermic fertilization in vitro and blastocyst transfer to uterus (PMID 11245577). This suggests that the tasks of ZPs don’t end in the extracellular space as previously assumed, but there may be also intracellular functions yet to be discovered. The present study tested if experimentally induced degradation of intracellular ZP3 impacted on the development and transcriptome of mouse embryos. To this end we degraded ZP3 using its antibody in conjunction with the ubiquitin-protein ligase TRIM21. This method is known as 'Trim-away' (PMID 29153837). Briefly, in this method a cell (e.g. oocyte) expressing TRIM21 is supplied e.g. injected with a specific antibody to a protein of interest, in this case ZP3. As a result, the ternary complex (target protein-antibody-TRIM21) is destroyed in the proteasome. TRIM21 is here always to be understood as translation product of microinjected mCherry-Trim21 mRNA. We compared two experimental groups, as follows. Pronuclear-stage oocytes (B6C3F1 x CD1) were microinjected with approx. 100 picoliters of mix comprised of mCherry-Trim21 mRNA 0.2 mg/mL + anti-ZP3 antibody (Proteintech 21279-1-AP) 1 mg/mL + dextran beads 0.02 mg/mL, forming a group named 'Trim-away ZP3' group, in triplicate. As a reference, pronuclear-stage oocytes were microinjected with the same mixture as above, except that the antibody buffer was used in lieu of the antibody itself, in triplicate, forming a group named ‚no Trim'. To identify differently expressed genes we compared group 'Trim-away ZP3' with group ‘no Trim’. Ten hours after microinjection, embryos were collected and lysed for transcriptome analysis. Transcriptome analysis revealed that embryos of group 'Trim-away ZP3' and group ‘no Trim' differed in gene expression and were resolved in principal component analysis. The data support a conclusion that ZP3 found inside the embryo was not merely a remnant from oogenesis, but served an intracellular, post-fertilization role during mouse preimplantation development.
Project description:Mutation studies always defined the functions of the zona pellucida (ZP) as extracellular, namely: to encase the oocytes in ovarian follicles, to ensure species-specific sperm binding, and to dampen shear stress on the embryo surface. Therefore, mutations in the three ZP mouse genes ZP1, ZP2 or ZP3 cause primary infertility due to empty follicles, polyspermic fertilization or harmful contact between embryos and oviductal epithelium. However, the concepti of ZP2-null and ZP3-null oocytes were still unviable also when the defects were obviated by monospermic fertilization in vitro and blastocyst transfer to uterus (PMID 11245577). This suggests that the tasks of ZPs don’t end in the extracellular space as previously assumed, but there may be also intracellular functions yet to be discovered. The present study tested if experimentally induced degradation of intracellular ZP3 impacted on the development and transcriptome of mouse embryos. To this end we degraded ZP3 using its antibody in conjunction with the ubiquitin-protein ligase TRIM21. This method is known as 'Trim-away' (PMID 29153837). Briefly, in this method a cell (e.g. oocyte) expressing TRIM21 is supplied e.g. injected with a specific antibody to a protein of interest, in this case ZP3. As a result, the ternary complex (target protein-antibody-TRIM21) is destroyed in the proteasome. TRIM21 is here always to be understood as translation product of microinjected mCherry-Trim21 mRNA. We compared two experimental groups, as follows. Pronuclear-stage oocytes (B6C3F1 x CD1) were microinjected with approx. 100 picoliters of mix comprised of mCherry-Trim21 mRNA 0.2 mg/mL + buffer of ZP3 antibody + dextran beads 0.02 mg/mL as tracer, forming a group named 'Trim21 overexpression', in quadruplicate. As a reference, pronuclear-stage oocytes were microinjected with mCherry-Trim21 mRNA 0.2 mg/mL + anti-ZP3 antibody (Proteintech 21279-1-AP) 1 mg/mL + dextran beads, forming a group named 'Trim-away ZP3' group, in triplicate. To identify differently expressed genes we compared group 'Trim-away ZP3' with group 'Trim21 overexpression'. In addition, a single 'non-manipulated' sample was also incuded merely to confirm that Trim21 was detectable in the two experimental groups, but not in the non-microinjected embryos. On the day after microinjection, embryos were collected and lysed for transcriptome analysis. Those of group 'Trim21 overexpression' were at the 2-cell stage so as the non-manipulated embryos, whereas those of group 'Trim-away ZP3' were arrested at the 1-cell stage. Transcriptome analysis revealed that embryos of group 'Trim-away ZP3' and 'group 'Trim21 overexpression' differed in the expression of 197 of 11137 genes (t test, FDR<0.05). The data support a conclusion that ZP3 found inside the embryo was not merely a remnant from oogenesis, but served an intracellular, post-fertilization role during mouse preimplantation development.
Project description:It is often desirable to be able to regulate or impair the expression of specific genes to study early developmental events in the mammalian embryo. While DNA and RNA methods are routine, methods using proteins are still in their infancy. When proteins in the cell encounter a specific antibody and the ubiquitin-protein ligase TRIM21, a ternary complex forms with the target protein, leading to its rapid and acute degradation – hence the name ‘Trim-Away'. However, there are many unknowns in this new endeavour. First and foremost, the extent to which endogenous proteins can be depleted depends on their amount in relation to the amount of exogenous antibody, which is limited by the microinjection procedure. Secondly, the depletion of the protein must be sustained over days. Using mass spectrometry and the iBAQ algorithm, we estimate the amount of proteins found in preimplantation mouse embryos. Most of these amounts are tractable with the microinjection method presented here, which supplies 10E-4 picomoles of antibody contained in 100 picolitres, before incurring toxic effects on mouse development. Building on these data, we demonstrate the feasibility of protein knock-down for a gene which is essential in the preimplantation mouse embryo, namely TEA domain family member 4 (Tead4). Knock-down persists long enough to result in a phenotype which is entirely consistent with that of the null mutation and the RNA interference: significantly reduced mRNA expression of TEAD4 target genes Cdx2 and Gata3, failure of CDX2 nuclear translocation and the embryo’s inability to implant. We conclude that at least for a time window of 3-4 days of preimplantation development, protein depletion is on the rise as a valid alternative to DNA and RNA methods.
Project description:The first lineage differentiation in mammals gives rise to the inner cell mass (ICM) and the trophectoderm (TE). In mice, TEAD4 is a master regulator of TE commitment, as it regulates the expression of other TE-specific genes and its ablation prevents blastocyst formation, but its role in other mammals remains unclear. TEAD4 ablation in bovine embryos did not impede TE differentiation or blastocyst formation, but a transcriptomic analysis was performed to see if there were any transcriptomic anomalies in knockout embryos.
Project description:The TEAD (1-4) transcription factors comprise the conserved TEA/ATTS DNA binding domain recognising the MCAT element in the promoters of muscle-specific genes. Despite extensive genetic analysis, the function of TEAD factors in muscle differentiation has proved elusive due to redundancy amongst the family members. Expression of the TEA/ATTS DNA binding domain that acts a dominant negative repressor of TEAD factors in C2C12 myoblasts inhibits their differentiation, while selective shRNA knockdown of TEAD4 results in abnormal differentiation characterised by the formation of shortened myotubes. Chromatin immunoprecipitation coupled to array hybridisation (ChIP-chip) shows that TEAD4 occupies 867 promoters including those of myogenic miRNAs. We show that TEAD factors cooperate with MYOD1 to directly induce Myogenin, CDKN1A and Caveolin 3 expression to promote myoblast differentiation and fusion. RNA-seq identifies a novel set of TEAD4 target genes encoding muscle structural and regulatory proteins and those required for the unfolded protein response. In contrast, TEAD4 represses expression of the growth factor CTGF and Cyclin D1 to promote differentiation. Together these results show that TEAD factor activity is essential for C2C12 cell differentiation and define a novel and nonredundant role for TEAD4 in regulating the unfolded protein response. C2C12 cells were infected with retrotiviral vector expressing Flag-HA-Tagged TEAD4 or with empty control vector and selected in the continouos presence of puromycin. Infected cell populations were then differentiated for 5 days in DMEM medium with 2% horse serum and fixed in 0.4% formaldehyde.
Project description:We have identified TEAD4 as a key prognosis factor in colorectal cancer. To elucidate the potentail mechanism and function of TEAD4 in colorectal caner, we generated two stable cell lines expressing different shRNA targeting TEAD4 in the mesenchymal-like LoVo cells and the differential genes were detected by microarray. LoVo colorectal cancer cells stably expressing pLKO.1 control shRNA or sh1_shTEAD4 or sh2_shTEAD4
Project description:In metazoans, maternal factors deposited in the ooplasm during oocyte growth are largely responsible for the control of initial development of the newly formed embryo. The gradual handover from oocytic to embryonic control, known as oocyte-to-embryo or maternal-to-zygotic transition, involves de novo synthesis of new embryonic factors (embryonic genome activation) as well as the timely degradation of preexisting maternal factors deposited in oocytes as transcripts or proteins. Nevertheless, the role of the protein deposits largely remains undeciphered. In order to study these deposits, genetic knockouts and knockdown systems are not suited because they do not react with the protein that has already been deposited. Targeted proteolysis can be accomplished with the 'Trim-away' method (PMID 29153837). Building on our proteomic datasets and our own adaptation of the Trim-away method (PMID 31638890), we demonstrate a large deposit of COP9 signalosome complex subunit 3 (COPS3) protein in mouse oocytes, and its critical role during the oocyte-to-embryo transition. COPS3 protein depletion in zygotes causes 2-cell arrest, at variance with the original report describing early postimplantation lethality (PMID 12972600). We conclude that peri-implantation demise was possibly the second time when the gene function was needed in development, while earlier functions had been hidden by maternal deposits. In the Trim-away method (PMID 29153837) a cell expressing the ubiquitin-protein ligase TRIM21 is supplied e.g. injected with a specific antibody to a protein of interest. As a result, the ternary complex (target protein-antibody-TRIM21) is destroyed in the proteasome. To test for the requirement of COPS3 in early mouse development, we chose to deplete COPS3 using its antibody in conjunction with TRIM21. To distinguish between depletion and inhibition of the target protein, we also tested the antibody alone. In total, we examined four groups, as follows. Pronuclear (PN)-stage oocytes (B6C3F1 x CD1) were microinjected with 100 picoliters of mix comprised of: Trim21 mRNA 0.2 mg/mL + dextran beads as tracer (named 'group 2'); Trim21 mRNA 0.2 mg/mL + anti-COPS3 antibody 0.5 mg/mL + dextran beads as tracer (named 'group 3'); anti-COPS3 antibody 0.5 mg/mL + dextran beads as tracer (named 'group 4'). Antibody was ab79698 from AbCam, column-purified twice to remove preservatives. These groups were compared with non-injected PN oocytes (named 'group 1'). Each group was produced in duplicate (replicate '.0' and replicate '.1'). On the day after microinjection, late 2-cell embryos were collected and lysed for transcriptome analysis. Zygotes of groups 3 and 4 presented stunted progression to the 2-cell stage, in contrast to the almost full rates of the zygotes of groups 1 and 2. Transcriptome analysis revealed that embryos group 2 are very similar to those of group 1 (97 differently expressed mRNAs), whereas embryos of groups 3 and 4 differ from those of group 1 by 3499 and 973 mRNAs, respectively (fold change ≥2, p≤0.05; Student’s t test).