XB-ART-55380
Genes Cells
December 1, 2018;
23
(12):
998-1008.
Developmental gene expression patterns in the brain and liver of Xenopus tropicalis during metamorphosis climax.
Abstract
Thyroid hormones (THs) induce metamorphosis in amphibians, causing dynamic changes, whereas mammalian newborns undergo environmental transition from placenta to open air at birth. The similarity between amphibian metamorphosis and the mammalian perinatal periods has been repeatedly discussed. However, a corresponding developmental gene expression analysis has not yet been reported. In this study, we examined the developmental gene expression profiles in the
brain and
liver of Xenopus tropicalis during metamorphosis
climax and compared them to the respective gene expression profiles of newborn rodents. Many upregulated genes identified in the
tadpole brain during metamorphosis are also upregulated in the rodent
brain during the first three postnatal weeks when the TH surge occurs. The upregulation of some genes in the
brain was inhibited in
thyroid hormone receptor α (TRα) knockout tadpoles but not in TRβ-knockout tadpoles, implying that
brain metamorphosis is mainly mediated by TRα. The expression of some genes was also increased in the
liver during metamorphosis
climax. Our data suggest that the rodent
brain undergoes TH-dependent remodeling during the first three postnatal weeks as observed in X. tropicalis during the
larva-to-adult metamorphosis.
PubMed ID:
30294949
Article link:
Genes Cells
Grant support:
[+]
25430089 A Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology, Japan, 26440057 A Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology, Japan
Species referenced:
Xenopus laevis
Genes referenced:
alb
arg1
ass1
atp1a2
atp1b3
cadm1
cadm2
cadm3
cdh2
cps1
dlg4
kcnj10
mag
mbp
nectin1
nectin3
nefl
nefm
otc
scn4b
slc12a5
syt2
thra
thrb
tubb3
XB22063245 [provisional:fxyd2]
GO keywords:
metamorphosis
Article Images:
[+] show captions
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Figure 1
Developmental expression of neural tissue‐related genes in the X. tropicalis brain. qRT‐PCR was conducted using total cellular brain RNA and gene‐specific primers (Supporting Information Table S2). The relative mRNA expression level of the indicated gene to EF‐1α mRNA is presented. Data are expressed as mean ± SD (biological replicate number = 5–7)
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Figure 2
Developmental expression of synapse‐related genes in the X. tropicalis brain. qRT‐PCR was conducted using total cellular brain RNA and gene‐specific primers (Supporting Information Table S2). The relative mRNA expression level of the indicated gene to EF‐1α mRNA is presented. Data are expressed as mean ± SD (biological replicate number = 5–7)
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Figure 3
Expression of neural tissue‐related and synapse‐related genes in the brain of NF stage 61 wild‐type and TR‐knockout tadpoles. Total cellular RNA was extracted from brains of NF stage 61 wild‐type, TRα‐knockout, and TRβ‐knockout tadpoles, and qRT‐PCR was conducted using gene‐specific primers (Supporting Information Table S2). The relative mRNA expression level of the indicated gene to EF‐1α mRNA is presented. Data are expressed as mean ± SD. Biological replicate numbers of wild‐type, TRα‐knockout, and TRβ‐knockout brain samples are five, five, and four, respectively. Statistical significance by comparison of TRα‐knockout tadpoles with wild‐type and TRβ‐knockout tadpoles were assessed using the Tukey's test. *p <0.05, **p <0.01
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Figure 4
Developmental expression of albumin and urea cycle enzyme genes in liver of X. tropicalis. qRT‐PCR was conducted using total cellular liver RNA and gene‐specific primers (Supporting Information Table S2). The relative mRNA expression level of the indicated gene to EF‐1α mRNA is represented. Data are expressed as mean ± SD (biological replicate number = 4–6)
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Figure 5
Developmental expression of TRα and TRβ genes in the brain and liver of X. tropicalis. qRT‐PCR was conducted using total cellular brain and liver RNAs and gene‐specific primers (Supporting Information Table S2). The relative mRNA expression level of the indicated gene to EF‐1α mRNA is presented. Data are expressed as mean ± SD. The biological replicate numbers are 5–7 (a, b) and 4–6 (c, d)
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Supplementary Figure 1. Expression of neural tissue-related genes in the brains of stage-61 wild-type and
TR-knockout tadpoles. Total cellular RNA was extracted from brains of NF stage-61 wild-type, TRα knockout,
and TRβ knockout tadpoles, and qRT-PCR was conducted using gene-specific primers (Table S2 in Supporting
Information). The relative mRNA expression level of the indicated gene to EF-1α mRNA is presented. Data are
expressed as mean ± SD. Biological replicate numbers of wild-type, TRα-knockout, and TRβ-knockout brain
samples are five, five, and four, respectively.
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Supplementary Figure 2. Developmental expression of albumin and urea cycle enzyme genes in liver
of R. catesbeiana. qRT-PCR was conducted using total cellular liver RNA and gene-specific primers (Table
S2 in Supporting Information). Tadpoles were staged according to the Nieukoop and Faber method. The
relative mRNA expression level of the indicated gene to EF-1α mRNA is represented.
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