Background Within the basic region‐helix‐loop‐helix (bHLH)‐PAS family of transcription factors, Arnt and Arnt2 play unique roles; these two factors not only heterodimerize with themselves, but also with other members of this family and they act as transcription regulators which bind to specific DNA elements. Whereas Arnt is broadly expressed in various tissues, the expression of Arnt2 is known to be limited to the neural tissues. Results To elucidate the function of Arnt2 in detail, we cloned the mouse Arnt2 gene and its gene structure was determined. We subsequently generated germ line Arnt2 mutant mice by gene targeting technology. Heterozygous Arnt2 mice were viable, but homozygous Arnt2 gene knockout mice died shortly after birth. Histological and immunological analyses revealed that the supraoptic nuclei (SON) and the paraventricular nuclei (PVN) are hypocellular. Moreover, secretory neurones identified by the expression of neurosecretory hormone such as arginine vasopressin, oxytocin, corticotrophin‐releasing hormone and somatostatin are completely absent in SON and PVN in the mutant Arnt2 mice. Consistent with these observations, prospective SON and PVN neurones which express Brn2 appeared around E13.5 in the mantle zone, but no neurones which expressed the neurosecretory hormones were found in the SON and PVN regions. Conclusions These data show that the transcription factor Arnt2 controls the development of the secretory neurones at the later or final stages of differentiation rather than at the beginning stage. Strikingly similar observations have been reported with the Sim1 deficient mice. Taken together, our results demonstrate that Arnt2 is an indispensable transcription factor for the development of the hypothalamus, and suggest that Arnt2 is an obligatory partner molecule of Sim1 in the developmental process of the neuroendocrinological cell lineages.

Tomonori Hosoya

Yoshihito Oda

Satoru Takahashi

Masanobu Morita

Shimako Kawauchi

Masatsugu Ema

Masayuki Yamamoto

Yoshiaki Fujii‐Kuriyama

Genes to Cells

GENES TO CELLS 为发表描述分子和细胞生物学重要方面的论文提供了一个国际论坛。该杂志旨在发表在相关领域提供概念性进展的论文。将特别强调旨在了解生物学事件的基本机制的工作。

Genes to Cells is an international forum dedicated to publishing important research papers in the field of molecular and cellular biology. The journal aims to present conceptual advancements in related areas, with a particular emphasis on studies that seek to understand the fundamental mechanisms underlying biological events.

《Genes to Cells》是一个国际论坛，专注于发表分子和细胞生物学领域的重要研究论文。该杂志旨在发布在相关领域内提供概念性进展的研究成果，特别强调揭示生物学事件基本机制的研究工作。

Defective development of secretory neurones in the hypothalamus of Arnt2‐knockout mice

Whereas Arnt is broadly expressed in various tissues, the expression of Arnt2 is known to be limited to the neural tissues.

Category	Quartile
生物学	4
生物学, 细胞生物学	4
生物学, 遗传学	4

Defective development of secretory neurones in the hypothalamus of Arnt2‐knockout mice

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Journal Info

Category	Quartile
GENETICS & HEREDITY	4