Mol Med Rep 15: [Related article:] 297–304, 2017; DOI:
10.3892/mmr.2016.6030
Following the publication of this paper, it was drawn
to the Editor's attention by a concerned reader that, in the
“Protein extraction and western blotting” subsection of the
Materials and methods on p. 299, it was reported that 30 ng samples
of protein were separated using SDS-PAGE, a concentration that
would be three orders of magnitude lower than what is typical.
Furthermore, regarding the “Chromatin immunoprecipitation (ChIP)
assay” subsection of the Materials and methods on p. 298, the
primer sequences described for targeting of the Msx2 promoter and
the GAPDH control were identical to the sequences of the Msx2 and
GAPDH primers reported in Table I, which were those used for
RT-qPCR analysis of cDNA derived from reverse-transcribed mRNA.
RT-qPCR primers are designed to target exon sequences in cDNA,
whereas ChIP primers are designed to target genomic promoter
regions; therefore, these primers would not have been expected to
have shared identical sequences, given that physically distinct
genomic regions were being targeted.
In their replies to these queries, the authors have
confirmed that “30 ng” was a typo, and in the relevant subsection
of the Materials and methods section, this should have been written
as “30 μg”. Concerning the nature of the primer sequences, the
authors confirmed that the same GAPDH primer was in fact used as a
negative primer control for both the ChIP and the RT-qPCR analyses.
However, the sequences used for the Msx gene for the RT-qPCR
analysis, as correctly presented in Table I, were inadvertently
copied across to the “Chromatin immunoprecipitation (ChIP)
assay” subsection of the Materials and methods. In this section
(p. 299, left-hand column, sentence commencing on line 4), the
sequences of these primers should have been written as follows (the
changed primer sequences are highlighted in bold): “Primers
(forward AGT GCT GCA GTT GGT CAT TG and reverse CCT GCA
AAT AAC GGG GTT CA) were used to amplify the Msx2 promoter”.
The region from −1,200 to +100 bp relative to the Msx2
transcription start site (TSS) was selected as the sequence of
interest. The RT-PCR primers for GAPDH were used as control
primers.
In connection with the issue of presenting the
correct sequences for the Msx gene for the RT-qPCR analysis,
the authors have realized that Fig.
4B was labeled incorrectly. As described in the Materials and
methods and the Results sections, the ChIP assay was performed to
detect the Msx2 promoter region, rather than the Bcl11b promoter.
The labeling for the lanes of the gel in Fig. 4B has therefore been corrected to
reflect this, and the revised version of Fig. 4 is shown on the next page. In
addition, certain corrections were required to the legend for this
figure, and the specific changes that have been made are
highlighted as follows in bold: “(B) PCR products of ChIP assay
were verified by 2% agarose gel electrophoresis. Bcl11b,
anti-Bcl11b antibody; input, cell lysate; Positive control,
anti-RNA polymerase II antibody; GAPDH, GAPDH primer; pMsx2,
Msx2 promoter primer; Msx2, Msx2 primer.”
 | Figure 4.Msx2 regulates enamel-associated
genes. Msx2 is a target gene of the transcription factor Bcl11b, as
verified by ChIP assay. (A) Knockdown of Bcl11b led to a
significant decrease in Msx2 expression. *P<0.05, **P<0.005,
n=3. (B) (B) PCR products of ChIP assay were verified by 2% agarose
gel electrophoresis. Bcl11b, anti-Bcl11b antibody; input, cell
lysate; Positive control, anti-RNA polymerase II antibody; GAPDH,
GAPDH primer; pMsx2, Msx2 promoter primer; Msx2, Msx2
primer. (C) Analysis of relative fold enrichment of ChIP.
Quantitative PCR result between the Bcl11b experimental group and
the positive control group. Student's t-test was used for
statistical analysis. *P<0.05, n=3. (D) Relative expression of
enamel-associated genes following Msx2 overexpression. *P<0.05,
***P<0.001, n=3. ns, not significant; Bcl11b, B-cell
CLL/lymphoma 11B; Msx2, Msh homeobox 2; Amelx, amelogenin,
X-linked; Ambn, ameloblastin; Enam, enamelin; Mmp20, matrix
metallopeptidase 20; Klk4, kallikrein related peptidase 4; PCR,
polymerase chain reaction. |
The authors confirm that these errors did not affect
the overall conclusions reported in this study. All the authors
agree with the publication of this corrigendum, and the authors are
grateful to the Editor of Molecular Medicine Reports for
allowing them the opportunity to publish this. The authors regret
that these errors were included in the paper, and apologize to the
readership for any inconvenience caused; they also thank the reader
for drawing these matters to their attention.
