Correction to “maea affects head formation through β-catenin degradation during early Xenopus laevis development”

Abstract

Goto, T., & Shibuya, H. (2023). maea affects head formation through β-catenin degradation during early Xenopus laevis development. Development, Growth & Differentiation, 65(1), 29–36. https://doi.org/10.1111/dgd.12828

In this article, the German letter “Eszett: ß” was used where the Greek letter “beta: β” should have been used in all cases.

The following points need to be corrected:

In the title,

“maea affects head formation through β-catenin degradation during early Xenopus laevis development”

In the Abstract,

“β-Catenin protein stability is a key factor in canonical Wnt signaling.”

“Several E3 ubiquitin ligases contribute to β-catenin degradation through the ubiquitin/proteasome system.”

“The expression levels of the Wnt target genes nodal homolog 3, gene 1 (nodal3.1), and siamois homeodomain 1 (sia1), which were induced by injection with β-catenin mRNA, were reduced by maea.S mRNA co-injection. maea.S overexpression at the anterior dorsal region enlarged head structures, whereas Maea knockdown interfered with head formation in Xenopus embryos.”

“Maea.S decreased and ubiquitinated β-catenin protein.”

“β-catenin-4KRs protein, which mutated the four lysine (K) residues known as ubiquitinated sites to arginine (R) residues, was also ubiquitinated and degraded by Maea.S.”

In the KEYWORDS,

“degradation, maea, β-catenin, ubiquitination, Xenopus laevis”

In the INTRODUCTION (first paragraph),

“The key aspect of Wnt signalling is β-catenin protein stability. Disheveled segment polarity protein (Dvl) is recruited at the cell membrane and prevents β-catenin degradation under the Wnt-on state.”

“Under the Wnt-off state, Axin1, adenomatous polyposis coli (Apc), casein kinase 1 alpha 1 (Csnk1α1), and glycogen synthase kinase 3 beta (Gsk3β) form the destruction complex to phosphorylate β-catenin protein (Liu et al., 2002).”

“Phosphorylated β-catenin is ubiquitinated by E3 ubiquitin ligases, such as beta-transducin repeat-containing E3 ubiquitin-protein ligase (Btrc), and is then degraded by the proteasome system.”

In the INTRODUCTION (third paragraph),

“There are four lysine residues known as ubiquitinated sites in β-catenin protein. Both lysine residues 19 and 49 are ubiquitinated by Btrc (Winer et al., 2006) and jade family PHD finger 1 (Jade1) (Chitalia et al., 2008).”

“Additionally, Siah E3 ubiquitin-protein ligase 1 (Siah1) ubiquitinates β-catenin at lysine residues 666 and 671 (Dimitrova et al., 2010).”

“HECT, UBA, and WWE domain containing E3 ubiquitin protein ligase 1 (Huwe1) and SNF2 histone linker PHD RING helicase, E3 ubiquitin protein ligase (Shprh) are also related to β-catenin protein degradation, but the sites they ubiquitinate have not been identified (Dominguez-Brauer et al., 2017; Qu et al., 2016).”

In the INTRODUCTION (fourth paragraph),

“The Glucose-Induced degradation Deficient (GID) complex also contributes to β-catenin ubiquitination and destruction.”

“WD repeat domain 26 (Wdr26), a scaffold protein in the GID complex, degrades β-catenin by binding to Axin1 and is required for head formation in Xenopus (Goto et al., 2016).”

“Both human Maea and Rmnd5a ubiquitinate human β-catenin, and their knockdown increases human β-catenin stability in HEK 293 T cells (Sato et al., 2020).”

“Therefore, Xenopus Maea could also play an important role in β-catenin degradation in Xenopus.”

“However, whether β-catenin protein degradation by Maea occurs in and affects Xenopus development remains unknown.”

“Here, we investigated the effects of Xenopus Maea on early Xenopus development through β-catenin degradation.”

In the MATERIALS AND METHODS (Section 2.1),

“The following primers were used to create a β-catenin-4KRs construct with four lysine (K) to arginine (R) mutations at lysine residues 19, 49, 666, and 671 in the β-catenin amino acid sequence:…”

In the MATERIALS AND METHODS (Section 2.2),

“Additionally, the following primer pair was used for RT-PCR analysis of β-catenin expression:…”

In the MATERIALS AND METHODS (Section 2.5),

“For RT-PCR analysis and observing the phenotypes of the injected embryos, we microinjected with maea.S mRNA (250, 500, or 1000 pg/blastomere), β-catenin mRNA (25 or 50 pg/blastomere), β-catenin-4KRs mRNA (25 or 50 pg/blastomere),…”

“We microinjected maea.S-FLAG mRNA (500 pg/blastomere) and MYC-β-catenin mRNA (50 pg/blastomere) into four animal blastomeres of 8-cell embryos to obtain lysates.”

In the RESULTS AND DISCUSSION (Section 3.2, first paragraph),

“Maea.S degraded and ubiquitinated β-catenin”

“Knockdown of human Maea suppressed human β-catenin protein degradation (Sato et al., 2020); therefore, we hypothesised that Xenopus maea.S might also regulate the amount of β-catenin protein in Xenopus.”

In the figure legend of Figure 2,

“β-catenin degradation and ubiquitination by Maea.S.”

“(a) WB of ectopically expressed Xenopus β-catenin protein in HEK 293 T cells.”

“(b) WB of lysates of Xenopus animal cap cells from embryos (st. 9) injected with MYC-β-catenin mRNA (50 pg/blastomere).”

“(c) Cycloheximide chase assay. maea.S-FLAG plasmid was transfected at 24 h after MYC-β-catenin plasmid transfection in HEK 293T cells.”

“(d) Interaction between ectopically expressed Xenopus maea.S and β-catenin in HEK 293T cells.”

“(e) WB of immunoprecipitates of ubiquitinated β-catenin protein treated with MG-132 (10 μM, 4 h) 24 h after transfection in HEK293T cells.”

“(g) RT-PCR analysis of the animal caps from embryos injected with β-catenin mRNA (50 pg/blastomere).”

In the RESULTS AND DISCUSSION (Section 3.2, first paragraph),

“Therefore, we investigated whether Xenopus maea.S overexpression changed the amount of Xenopus β-catenin protein.”

“In HEK 293T cells, transfection of maea.S plasmid reduced the amount of ectopically expressed β-catenin protein in a dose-dependent manner (Figure 2a).”

“Additionally, in Xenopus animal caps, ectopically expressed β-catenin protein decreased after injection with maea.S mRNA (Figure 2b).”

“Furthermore, the cycloheximide chase assay showed that the transfection of maea.S plasmid promoted β-catenin protein degradation in the short term (4 h) (Figure 2c).”

“Moreover, the immunoprecipitation assay revealed that Maea.S also bound to and ubiquitinated β-catenin similar to human proteins, as previously reported (Sato et al., 2020) (Figure 2d,e).”

“These results suggest that the degradation system of β-catenin protein by Maea might be similar between humans and Xenopus.”

In the RESULTS AND DISCUSSION (Section 3.2, second paragraph),

“Because alteration of the transcriptional level of β-catenin by maea was not previously investigated (Sato et al., 2020), we used RT-PCR to confirm β-catenin transcript expression in animal caps of the maea.S mRNA-injected embryos.”

“As a result, maea.S mRNA overexpression slightly increased β-catenin transcripts (Figure 2f).”

“This suggests that the decrease in β-catenin protein by Maea.S does not occur at the transcriptional level, and the reduction of β-catenin protein by Maea.S upregulates β-catenin transcription to compensate for its protein reduction.”

“Moreover, β-catenin mRNA overexpression in animal caps slightly increased maea expression (Figure 2g).”

“In Xenopus, there may be a system for mutually controlling transcript levels to maintain a steady level of β-catenin protein.”

In the RESULTS AND DISCUSSION (Section 3.3, title),

“Overexpression of maea.S mRNA inhibited the effects of β-catenin”

In the RESULTS AND DISCUSSION (Section 3.3, first paragraph),

“To confirm the effect of β-catenin protein degradation by Maea.S in Xenopus development,…”

In the RESULTS AND DISCUSSION (Section 3.3, second paragraph),

“Because anterior Wnt inhibition is necessary for head formation (De Robertis & Kuroda, 2004; Ding et al., 2018; Kumar et al., 2021; Niehrs, 2022), the enlargement of head structures of embryos injected with maea.S mRNA might be caused by β-catenin protein degradation in the anterior region.”

“Therefore, Rmnd5a might also contribute to β-catenin protein degradation by working with Maea in Xenopus in a similar manner to previously reported human cultured cells (Sato et al., 2020).”

In the RESULTS AND DISCUSSION (Section 3.3, third paragraph),

“When we injected a low dose of β-catenin mRNA into ventral blastomeres of 4-cell embryos,…”

“Wnt target gene expression in embryos ventrally injected with β-catenin mRNA also decreased by co-injection with maea.S mRNA (Figure 3e).”

“These results suggest that maea.S may function as a gene that suppresses excessive Wnt activities through the degradation of β-catenin protein during early development.”

In the RESULTS AND DISCUSSION (Section 3.4, first paragraph),

“These findings reveal that maea might contribute to head formation by inhibiting the Wnt activity through β-catenin protein degradation during early embryogenesis.”

In the figure legend of Figure 3,

“Effects of β-catenin on head and secondary axis formation by maea.S.”

“(c) Phenotypes of embryos (st. 30) when injected with β-catenin mRNA or co-injected with maea.S mRNA into ventral blastomeres at the 4-cell stage.”

“(e) RT-PCR analysis of the ventral sectors from embryos injected with β-catenin mRNA (50 pg/blastomere) or co-injected with maea.S mRNA (500 pg/blastomere).”

In the figure legend of Figure 4,

“Inhibition effects of maea.S on the β-catenin-4KRs construct.”

“(a) WB of ectopically expressed β-catenin-4KRs in HEK 293T cells.”

“(b) Interaction between ectopically expressed Maea.S and β-catenin- 4KRs in HEK 293T cells.”

“(c) WB of ubiquitinated β-catenin-4KRs treated as described in Figure 2e.”

“(d) The appearance rates of embryo phenotypes when injected with β-catenin-4KRs mRNA or co-injected with maea.S mRNA into ventral blastomeres at the 4-cell stage (see Figure 3c,d).”

“(e) RT-PCR analysis of the ventral sectors of embryos injected with β-catenin-4KRs mRNA (50 pg/blastomere) or co-injected with maea.S mRNA (500 pg/blastomere).”

In the RESULTS AND DISCUSSION (Section 3.5, title),

“Maea.S might ubiquitinate unknown lysine residues of β-catenin”

In the RESULTS AND DISCUSSION (Section 3.5, first paragraph),

“In vertebrates, the amino acid sequence of β-catenin involves 26 lysine residues, which are conserved amongst species.”

“In the GID complex proteins, Wdr26 and Rmnd5a also seem to contribute to β-catenin degradation…”

In the RESULTS AND DISCUSSION (Section 3.5, second paragraph),

“To investigate whether Maea.S ubiquitinates unknown lysine residues of β-catenin protein, we used a β-catenin-4KRs construct with four lysine to arginine mutations at 19, 49, 666, and 671 lysine residues.”

“In HEK 293T cells, maea.S plasmid transfection reduced β-catenin-4KRs protein amounts (Figure 4a).”

“Moreover, Maea.S also bound to and ubiquitinated β-catenin-4KRs protein (Figure 4b,c).”

“The appearance rates of the secondary axis with complete and partial head structures of embryos injected with β-catenin-4KRs mRNA were decreased by maea.S mRNA co-injection (Figure 4d).”

“Wnt target gene expression of embryos ventrally injected with β-catenin-4KRs mRNA was also reduced by co-injection with maea.S mRNA (Figure 4e).”

“These results demonstrate that β-catenin protein degradation by Maea.S might be due to β-catenin protein ubiquitination at unknown lysine residues.”

“However, because degradation of β-catenin-4KRs protein by Maea.S was less efficient than that of β-catenin protein, Maea.S might also ubiquitinate parts of or all known lysine residues (Figures 2a and 4a).”

The online article has been corrected.

We apologize for this error.