Prdm8 regulates the morphological transition at multipolar phase during neocortical development.
Here, we found that the PR domain protein Prdm8 serves as a key regulator of the length of the multipolar phase by controlling the timing of morphological transition. We used a mouse line with expression of Prdm8-mVenus reporter and found that Prdm8 is predominantly expressed in the middle and upper intermediate zone during both the late and terminal multipolar phases. Prdm8 expression was almost coincident with Unc5D expression, a marker for the late multipolar phase, although the expression of Unc5D was found to be gradually down-regulated to the point at which mVenus expression was gradually up-regulated. This expression pattern suggests the possible involvement of Prdm8 in the control of the late and terminal multipolar phases, which controls the timing for morphological transition. To test this hypothesis, we performed gain- and loss-of-function analysis of neocortical development by using in utero electroporation. We found that the knockdown of Prdm8 results in premature change from multipolar to bipolar morphology, whereas the overexpression of Prdm8 maintained the multipolar morphology. Additionally, the postnatal analysis showed that the Prdm8 knockdown stimulated the number of early born neurons, and differentiated neurons located more deeply in the neocortex, however, majority of those cells could not acquire molecular features consistent with laminar location. Furthermore, we found the candidate genes that were predominantly utilized in both the late and terminal multipolar phases, and these candidate genes included those encoding for guidance molecules. In addition, we also found that the expression level of these guidance molecules was inhibited by the introduction of the Prdm8 expression vector. These results indicate that the Prdm8-mediated regulation of morphological changes that normally occur during the late and terminal multipolar phases plays an important role in neocortical development.
Laboratory of Neural Differentiation, Graduate School of Brain Science, Doshisha University, Kyoto, Japan ; Department of Molecular and Cellular Biology, Graduate School of Biostudies, Kyoto University, Kyoto, Japan.
Mayuko
M
Inoue
Laboratory of Neural Differentiation, Graduate School of Brain Science, Doshisha University, Kyoto, Japan.
Takao
T
Kuroda
Laboratory of Neural Differentiation, Graduate School of Brain Science, Doshisha University, Kyoto, Japan.
Aya
A
Honda
Laboratory of Neural Differentiation, Graduate School of Brain Science, Doshisha University, Kyoto, Japan.
Mariko
M
Komabayashi-Suzuki
Department of Molecular and Cellular Biology, Graduate School of Biostudies, Kyoto University, Kyoto, Japan.
Tae
T
Komai
Cellular Memory Laboratory, RIKEN, Saitama, Japan.
Yoichi
Y
Shinkai
Laboratory of Neural Differentiation, Graduate School of Brain Science, Doshisha University, Kyoto, Japan ; Japan Science and Technology Agency, PRESTO, Tokyo, Japan.
Ken-ichi
K
Mizutani
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002540:Cerebral Cortex / Q000254:growth & development / Q000378:metabolism*; D004268:DNA-Binding Proteins; D018274:Electroporation; D004622:Embryo, Mammalian; D005260:Female; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D017930:Genes, Reporter; D000076983:Histone Methyltransferases; D011495:Histone-Lysine N-Methyltransferase / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D007276:Injections, Intraventricular; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008813:Mice, Inbred ICR; D055495:Neurogenesis / Q000235:genetics*; D010957:Plasmids; D011247:Pregnancy; D014599:Uterus; D000097573:Red Fluorescent Protein
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D000076983:Histone Methyltransferases; D011495:Histone-Lysine N-Methyltransferase; D008164:Luminescent Proteins; D000097573:Red Fluorescent Protein; C054562:yellow fluorescent protein, Bacteria; C543643:PRDM8 protein, mouse