Sato Yuki, Hayashi Shinichi, Oe Souichi, Koike Taro, Nakano Yousuke, Seki-Omura Ryohei, Iwashita Hikaru, Hirahara Yukie, Kitada Masaaki
Department of Anatomy, Faculty of Medicine, Kansai Medical University, Osaka, Japan.
Faculty of Nursing, Kansai Medical University, Osaka, Japan.
Dev Growth Differ. 2025 Apr;67(3):136-148. doi: 10.1111/dgd.70001. Epub 2025 Feb 11.
In the M-phase, the nuclear membrane is broken down, nucleosomes are condensed as mitotic chromosomes, and transcription factors are generally known to be dislocated from their recognition sequences and dispersed to the cytoplasm. However, some transcription factors have recently been reported to remain on mitotic chromosomes and facilitate the rapid re-activation of the target genes in early G1-phase. Paired-like homeobox 2B (PHOX2B) is a transcription factor exhibiting chromosomal localization during M-phase. PHOX2B mutations are associated with congenital central hypoventilation syndrome, Hirschsprung disease, and neuroblastoma. In this study, we investigated PHOX2B chromosomal localization during M-phase through immunostaining and fluorescence recovery after photobleaching analysis to determine whether the chromosomal localization of disease-associated PHOX2B mutants is altered during M-phase. Missense mutations in the homeodomain and the frameshift mutation in the C-terminal domain disrupted the chromosomal localization of PHOX2B in M-phase, leading to its dispersion in the cell. Furthermore, a PHOX2B mutant with polyalanine expansion showed a line-shaped localization to the restricted region of mitotic chromosomes. Our findings suggest an association between the disease-associated mutations and defective chromosomal localization of transcription factors during M-phase. Further investigations of PHOX2B chromosomal localization during M-phase could reveal pathogenic mechanisms of such diseases.
在M期，核膜解体，核小体浓缩为有丝分裂染色体，并且通常已知转录因子会从其识别序列上脱离并分散到细胞质中。然而，最近有报道称一些转录因子会保留在有丝分裂染色体上，并在G1期早期促进靶基因的快速重新激活。配对样同源盒2B（PHOX2B）是一种在M期表现出染色体定位的转录因子。PHOX2B突变与先天性中枢性低通气综合征、先天性巨结肠病和神经母细胞瘤有关。在本研究中，我们通过免疫染色和光漂白后荧光恢复分析研究了M期PHOX2B的染色体定位，以确定疾病相关的PHOX2B突变体的染色体定位在M期是否发生改变。同源结构域中的错义突变和C末端结构域中的移码突变破坏了PHOX2B在M期的染色体定位，导致其在细胞中分散。此外，一个具有聚丙氨酸扩展的PHOX2B突变体在有丝分裂染色体的受限区域显示出线性定位。我们的研究结果表明疾病相关突变与M期转录因子的染色体定位缺陷之间存在关联。对M期PHOX2B染色体定位的进一步研究可能揭示此类疾病的致病机制。
