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Control of cortex development by ULK4, a rare risk gene for mental disorders including schizophrenia

View Article: PubMed Central - PubMed

ABSTRACT

Schizophrenia is a debilitating familial neuropsychiatric disorder which affects 1% of people worldwide. Although the heritability for schizophrenia approaches 80% only a small proportion of the overall genetic risk has been accounted for, and to date only a limited number of genetic loci have been definitively implicated. We have identified recently through genetic and in vitro functional studies, a novel serine/threonine kinase gene, unc-51-like kinase 4 (ULK4), as a rare risk factor for major mental disorders including schizophrenia. Now using the approach of in utero gene transfer we have discovered that Ulk4 plays a key modulatory role in corticogenesis. Knockdown of Ulk4 leads to significantly decreased cell proliferation in germinal zones and profound deficits in radial migration and neurite ramification. These abnormalities can be reversed successfully by Ulk4 gene supplementation. Ulk4 also regulated acetylation of α-tubulin, an important post-translational modification of microtubules. We conclude that Ulk4 plays an essential role in normal brain development and when defective, the risk of neurodevelopmental disorders such as schizophrenia is increased.

No MeSH data available.


Ulk4R cDNA successfully rescues the defective radial migration mediated by shRNA268.(A) Validation of Ulk4R cDNA. Panels of plasmids containing different DNA constructs were co-transfected into HEK293 cells. Western blotting with anti-c-Myc (top row) and anti-flag (mid-row) indicated that Ulk4R cDNA successfully restores the expression of Ulk4. Lane 1: co-transfection with plasmids containing control shRNA and Ulk4 cDNA; Lane 2: co-transfection with Ulk4 cDNA and shRNA268; Lane 3: co-transfection with control shRNA and Ulk4R cDNA; Lane 4: co-transfection with plasmids containing shRNA268 and Ulk4R cDNA. (B–D) Compared with the control group (B), the defective radial migration caused by shRNA268 (C) can be successfully rescued by Ulk4R cDNA (D). Bars = 100 μm in (B–D).
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f7: Ulk4R cDNA successfully rescues the defective radial migration mediated by shRNA268.(A) Validation of Ulk4R cDNA. Panels of plasmids containing different DNA constructs were co-transfected into HEK293 cells. Western blotting with anti-c-Myc (top row) and anti-flag (mid-row) indicated that Ulk4R cDNA successfully restores the expression of Ulk4. Lane 1: co-transfection with plasmids containing control shRNA and Ulk4 cDNA; Lane 2: co-transfection with Ulk4 cDNA and shRNA268; Lane 3: co-transfection with control shRNA and Ulk4R cDNA; Lane 4: co-transfection with plasmids containing shRNA268 and Ulk4R cDNA. (B–D) Compared with the control group (B), the defective radial migration caused by shRNA268 (C) can be successfully rescued by Ulk4R cDNA (D). Bars = 100 μm in (B–D).

Mentions: To further validate that the deficits described above were directly caused by Ulk4 knockdown, we designed and cloned shRNA268-resistant Ulk4 cDNA (Ulk4R cDNA) by introducing 7 point mutations into Ulk4 full length cDNA within the targeting locus without alteration of the amino acid sequence. We chose shRNA268 because of its potent knockdown ability which leads to the overt phenotypes in vivo (Fig. 4B–F). To determine the resistant capacity of Ulk4R cDNA against shRNA268, we transfected both of these two constructs into HEK293 cells and then determined the Ulk4 expression by western blotting. Our results showed that the reduced expression of Ulk4 caused by shRNA268 was recovered successfully by Ulk4R cDNA (Fig. 7A).


Control of cortex development by ULK4, a rare risk gene for mental disorders including schizophrenia
Ulk4R cDNA successfully rescues the defective radial migration mediated by shRNA268.(A) Validation of Ulk4R cDNA. Panels of plasmids containing different DNA constructs were co-transfected into HEK293 cells. Western blotting with anti-c-Myc (top row) and anti-flag (mid-row) indicated that Ulk4R cDNA successfully restores the expression of Ulk4. Lane 1: co-transfection with plasmids containing control shRNA and Ulk4 cDNA; Lane 2: co-transfection with Ulk4 cDNA and shRNA268; Lane 3: co-transfection with control shRNA and Ulk4R cDNA; Lane 4: co-transfection with plasmids containing shRNA268 and Ulk4R cDNA. (B–D) Compared with the control group (B), the defective radial migration caused by shRNA268 (C) can be successfully rescued by Ulk4R cDNA (D). Bars = 100 μm in (B–D).
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5037360&req=5

f7: Ulk4R cDNA successfully rescues the defective radial migration mediated by shRNA268.(A) Validation of Ulk4R cDNA. Panels of plasmids containing different DNA constructs were co-transfected into HEK293 cells. Western blotting with anti-c-Myc (top row) and anti-flag (mid-row) indicated that Ulk4R cDNA successfully restores the expression of Ulk4. Lane 1: co-transfection with plasmids containing control shRNA and Ulk4 cDNA; Lane 2: co-transfection with Ulk4 cDNA and shRNA268; Lane 3: co-transfection with control shRNA and Ulk4R cDNA; Lane 4: co-transfection with plasmids containing shRNA268 and Ulk4R cDNA. (B–D) Compared with the control group (B), the defective radial migration caused by shRNA268 (C) can be successfully rescued by Ulk4R cDNA (D). Bars = 100 μm in (B–D).
Mentions: To further validate that the deficits described above were directly caused by Ulk4 knockdown, we designed and cloned shRNA268-resistant Ulk4 cDNA (Ulk4R cDNA) by introducing 7 point mutations into Ulk4 full length cDNA within the targeting locus without alteration of the amino acid sequence. We chose shRNA268 because of its potent knockdown ability which leads to the overt phenotypes in vivo (Fig. 4B–F). To determine the resistant capacity of Ulk4R cDNA against shRNA268, we transfected both of these two constructs into HEK293 cells and then determined the Ulk4 expression by western blotting. Our results showed that the reduced expression of Ulk4 caused by shRNA268 was recovered successfully by Ulk4R cDNA (Fig. 7A).

View Article: PubMed Central - PubMed

ABSTRACT

Schizophrenia is a debilitating familial neuropsychiatric disorder which affects 1% of people worldwide. Although the heritability for schizophrenia approaches 80% only a small proportion of the overall genetic risk has been accounted for, and to date only a limited number of genetic loci have been definitively implicated. We have identified recently through genetic and in vitro functional studies, a novel serine/threonine kinase gene, unc-51-like kinase 4 (ULK4), as a rare risk factor for major mental disorders including schizophrenia. Now using the approach of in utero gene transfer we have discovered that Ulk4 plays a key modulatory role in corticogenesis. Knockdown of Ulk4 leads to significantly decreased cell proliferation in germinal zones and profound deficits in radial migration and neurite ramification. These abnormalities can be reversed successfully by Ulk4 gene supplementation. Ulk4 also regulated acetylation of α-tubulin, an important post-translational modification of microtubules. We conclude that Ulk4 plays an essential role in normal brain development and when defective, the risk of neurodevelopmental disorders such as schizophrenia is increased.

No MeSH data available.