Department of Anatomy and Neurobiology, University of Puerto Rico, Medical Sciences Campus (UPR-MSC), San Juan, PR, USA.
Oklahoma Medical Research Foundation (OMRF), Oklahoma City, OK, USA.
Gene Expr Patterns. 2020 Sep;37:119126. doi: 10.1016/j.gep.2020.119126. Epub 2020 Jul 11.
The Activating Transcription Factor 5 (ATF5) is a basic leucine-zipper (bZIP) transcription factor (TF) with proposed stress-protective, anti-apoptotic and oncogenic roles which were all established in cell systems. In whole animals, Atf5 function seems highly context dependent. Atf5 is strongly expressed in the rodent nose and mice knockout (KO) pups have defective olfactory sensory neurons (OSNs), smaller olfactory bulbs (OB), while adults are smell deficient. It was therefore proposed that Atf5 plays an important role in maturation and maintenance of OSNs. Atf5 expression was also described in murine liver and bones where it appears to promote differentiation of progenitor cells. By contrast in the rodent brain, Atf5 was first described as uniquely expressed in neuroprogenitors and thus, proposed to drive their proliferation and inhibit their differentiation. However, it was later also found in mature neurons stressing the need for additional work in whole animals. ATF5 is well conserved with two paralogs, atf5a and atf5b in zebrafish. Here, we present the expression patterns for both from 6 h (hpf) to 5day post-fertilization (dpf). We found early expression for both genes, and from 1dpf onwards overlapping expression patterns in the inner ear and the developing liver. In the brain, at 24hpf both atf5a and atf5b were expressed in the forebrain, midbrain, and hindbrain. However, from 2dpf and onwards we only detected atf5a expression namely in the olfactory bulbs, the mesencephalon, and the metencephalon. We further evidenced additional differential expression for atf5a in the sensory neurons of the olfactory organs, and for atf5b in the neuromasts, that form the superficial sensory organ called the lateral line (LL). Our results establish the basis for future functional analyses in this lower vertebrate.
激活转录因子 5 (ATF5) 是一种碱性亮氨酸拉链 (bZIP) 转录因子 (TF),具有应激保护、抗凋亡和致癌作用,这些作用均在细胞系统中得到证实。在整个动物中,Atf5 的功能似乎高度依赖于上下文。Atf5 在啮齿动物鼻子中强烈表达,Atf5 基因敲除 (KO) 幼鼠嗅觉感觉神经元 (OSN) 缺失,嗅球 (OB) 较小,而成人则嗅觉丧失。因此,有人提出 Atf5 在 OSN 的成熟和维持中发挥重要作用。Atf5 在小鼠肝脏和骨骼中也有表达,似乎促进祖细胞的分化。相比之下,在啮齿动物大脑中,Atf5 首先被描述为仅在神经祖细胞中表达,因此,被认为可驱动其增殖并抑制其分化。然而,后来也在成熟神经元中发现了 Atf5,这强调了在整个动物中需要进一步研究。ATF5 在斑马鱼中有两个同源物,即 atf5a 和 atf5b。在这里,我们从 6 小时(hpf)到 5 天受精后(dpf)呈现这两个基因的表达模式。我们发现这两个基因都有早期表达,从 1 天受精后(dpf)开始,在内耳和发育中的肝脏中表现出重叠的表达模式。在大脑中,在 24 小时受精后(hpf),atf5a 和 atf5b 都在大脑前脑、中脑和后脑中表达。然而,从 2 天受精后(dpf)开始,我们仅检测到 atf5a 在嗅球、中脑和后脑中表达。我们进一步证明了 atf5a 在嗅觉器官感觉神经元中的差异表达,以及 atf5b 在形成称为侧线 (LL) 的浅层感觉器官的神经丘中的差异表达。我们的结果为在这种低等脊椎动物中进行未来的功能分析奠定了基础。