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The Rat Homolog of the Schizophrenia Susceptibility Gene ZNF804A Is Highly Expressed during Brain Development, Particularly in Growth Cones.

Hinna KH, Rich K, Fex-Svenningsen Å, Benedikz E - PLoS ONE (2015)

Bottom Line: We found that expression of Zfp804A in most brain regions is developmentally regulated and peaks around birth, where after it decreases towards adult levels.Interestingly, before day 4, the protein is mostly found in the perinuclear region of the cell but at day 4, ZFP804A was instead found throughout the cell and particularly in the growth cones.In conclusion we demonstrate that Zfp804A increases in the rat brain at the time of birth, coinciding with neuronal differentiation.

View Article: PubMed Central - PubMed

Affiliation: Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.

ABSTRACT
A single nucleotide polymorphism in the ZNF804A gene, rs1344706, is associated with schizophrenia. The polymorphism has been suggested to alter fetal expression of ZNF804A. It has also been reported to be associated with altered cortical functioning and neural connectivity in the brain. Since developmental mechanisms are suggested in the pathophysiology for schizophrenia, expression of Zfp804A, the rat homolog of ZNF804A, was investigated in the developing rat brain. We found that expression of Zfp804A in most brain regions is developmentally regulated and peaks around birth, where after it decreases towards adult levels. This time point is developmentally the equivalent to the second trimester of fetal development in humans. An exception to this expression pattern is the hippocampus where the expression of Zfp804A appears to increase again in the adult brain. Using laser capture and quantitative PCR we found that Zfp804A mRNA expression in the adult rat hippocampus is highest in the CA1 sub region, where the overall firing rates of neurons is higher than in the CA3 region. In cultured cortical neurons Zfp804A mRNA expression peaked at day 4 and then decreased. The ZFP804A protein expression was therefore investigated with immunochemistry in such cultures. Interestingly, before day 4, the protein is mostly found in the perinuclear region of the cell but at day 4, ZFP804A was instead found throughout the cell and particularly in the growth cones. In conclusion we demonstrate that Zfp804A increases in the rat brain at the time of birth, coinciding with neuronal differentiation. We also show that ZFP804A is localized to growth cones of growing neurites. These data implicate ZFP804A in growth cone function and neurite elongation. The polymorphism rs1344706 lowers expression of ZNF804A during prenatal brain development. This may affect ZNF804A's role in cone function and neurite elongation leading to synaptic deficits and altered neural connectivity.

No MeSH data available.


Related in: MedlinePlus

Zfp804A mRNA expression in the adult rat hippocampus.(A) Adult rat section stained with toluidine. (B) Schematic illustration of the dissected regions of the hippocampal sub-regions CA1, CA3 and DG. (C) Relative Zfp804A expression in the three sub-regions of a rat hippocampus. The zfp804A primer set was used and data is presented as means ± SEM. Gapdh was used as a reference gene and n ≥ 4. There is a significant difference between CA1 and DG (*P < 0.05).
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pone.0132456.g002: Zfp804A mRNA expression in the adult rat hippocampus.(A) Adult rat section stained with toluidine. (B) Schematic illustration of the dissected regions of the hippocampal sub-regions CA1, CA3 and DG. (C) Relative Zfp804A expression in the three sub-regions of a rat hippocampus. The zfp804A primer set was used and data is presented as means ± SEM. Gapdh was used as a reference gene and n ≥ 4. There is a significant difference between CA1 and DG (*P < 0.05).

Mentions: The levels of Zfp804A mRNA did not change as much in the hippocampus as it did in the frontal cortex or cerebellum (Fig 1C). However, the same pattern can be seen, with high levels at P1 and a decrease at P5 to the lowest level of the time points investigated. Interestingly the highest levels of Zfp804A detected in the hippocampus were found in the adult samples. In fact these values are significantly higher than at P5 (P<0.05). We therefore investigated the expression levels of Zfp804A in animals aged 8–11 weeks, which corresponds to adolescence in the rats but the expression did not reach adult levels during this period. Since the dorsal and ventral parts of the hippocampus are functionally distinct, gene expression may differ [24]. The dorsal, ventral and medial part of the adult hippocampus were dissected, and the mRNA levels determined in the different parts. The results showed no difference in expression. We also investigated mRNA expression within the adult hippocampus using LMC (Fig 2). The results showed that the expression of Zfp804A was significantly higher in the CA1 subfield compared to that in DG (P < 0.05) (Fig 2C). The levels in CA3 were similar to that in DG, but when compared to the CA1, the difference did not reach significance.


The Rat Homolog of the Schizophrenia Susceptibility Gene ZNF804A Is Highly Expressed during Brain Development, Particularly in Growth Cones.

Hinna KH, Rich K, Fex-Svenningsen Å, Benedikz E - PLoS ONE (2015)

Zfp804A mRNA expression in the adult rat hippocampus.(A) Adult rat section stained with toluidine. (B) Schematic illustration of the dissected regions of the hippocampal sub-regions CA1, CA3 and DG. (C) Relative Zfp804A expression in the three sub-regions of a rat hippocampus. The zfp804A primer set was used and data is presented as means ± SEM. Gapdh was used as a reference gene and n ≥ 4. There is a significant difference between CA1 and DG (*P < 0.05).
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4493006&req=5

pone.0132456.g002: Zfp804A mRNA expression in the adult rat hippocampus.(A) Adult rat section stained with toluidine. (B) Schematic illustration of the dissected regions of the hippocampal sub-regions CA1, CA3 and DG. (C) Relative Zfp804A expression in the three sub-regions of a rat hippocampus. The zfp804A primer set was used and data is presented as means ± SEM. Gapdh was used as a reference gene and n ≥ 4. There is a significant difference between CA1 and DG (*P < 0.05).
Mentions: The levels of Zfp804A mRNA did not change as much in the hippocampus as it did in the frontal cortex or cerebellum (Fig 1C). However, the same pattern can be seen, with high levels at P1 and a decrease at P5 to the lowest level of the time points investigated. Interestingly the highest levels of Zfp804A detected in the hippocampus were found in the adult samples. In fact these values are significantly higher than at P5 (P<0.05). We therefore investigated the expression levels of Zfp804A in animals aged 8–11 weeks, which corresponds to adolescence in the rats but the expression did not reach adult levels during this period. Since the dorsal and ventral parts of the hippocampus are functionally distinct, gene expression may differ [24]. The dorsal, ventral and medial part of the adult hippocampus were dissected, and the mRNA levels determined in the different parts. The results showed no difference in expression. We also investigated mRNA expression within the adult hippocampus using LMC (Fig 2). The results showed that the expression of Zfp804A was significantly higher in the CA1 subfield compared to that in DG (P < 0.05) (Fig 2C). The levels in CA3 were similar to that in DG, but when compared to the CA1, the difference did not reach significance.

Bottom Line: We found that expression of Zfp804A in most brain regions is developmentally regulated and peaks around birth, where after it decreases towards adult levels.Interestingly, before day 4, the protein is mostly found in the perinuclear region of the cell but at day 4, ZFP804A was instead found throughout the cell and particularly in the growth cones.In conclusion we demonstrate that Zfp804A increases in the rat brain at the time of birth, coinciding with neuronal differentiation.

View Article: PubMed Central - PubMed

Affiliation: Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.

ABSTRACT
A single nucleotide polymorphism in the ZNF804A gene, rs1344706, is associated with schizophrenia. The polymorphism has been suggested to alter fetal expression of ZNF804A. It has also been reported to be associated with altered cortical functioning and neural connectivity in the brain. Since developmental mechanisms are suggested in the pathophysiology for schizophrenia, expression of Zfp804A, the rat homolog of ZNF804A, was investigated in the developing rat brain. We found that expression of Zfp804A in most brain regions is developmentally regulated and peaks around birth, where after it decreases towards adult levels. This time point is developmentally the equivalent to the second trimester of fetal development in humans. An exception to this expression pattern is the hippocampus where the expression of Zfp804A appears to increase again in the adult brain. Using laser capture and quantitative PCR we found that Zfp804A mRNA expression in the adult rat hippocampus is highest in the CA1 sub region, where the overall firing rates of neurons is higher than in the CA3 region. In cultured cortical neurons Zfp804A mRNA expression peaked at day 4 and then decreased. The ZFP804A protein expression was therefore investigated with immunochemistry in such cultures. Interestingly, before day 4, the protein is mostly found in the perinuclear region of the cell but at day 4, ZFP804A was instead found throughout the cell and particularly in the growth cones. In conclusion we demonstrate that Zfp804A increases in the rat brain at the time of birth, coinciding with neuronal differentiation. We also show that ZFP804A is localized to growth cones of growing neurites. These data implicate ZFP804A in growth cone function and neurite elongation. The polymorphism rs1344706 lowers expression of ZNF804A during prenatal brain development. This may affect ZNF804A's role in cone function and neurite elongation leading to synaptic deficits and altered neural connectivity.

No MeSH data available.


Related in: MedlinePlus