Kobayashi Yuki, Chiba Hiroaki, Amiya Noriko, Yamanome Takeshi, Mizusawa Kanta, Amano Masafumi, Takahashi Akiyoshi
School of Marine Biosciences, Kitasato University, Ofunato, Iwate, Japan.
Gen Comp Endocrinol. 2008 Sep 15;158(3):259-67. doi: 10.1016/j.ygcen.2008.07.015. Epub 2008 Aug 5.
Proopiomelanocortin (POMC) is the precursor of adrenocorticotropin, melanocyte-stimulating hormone, and endorphin. Barfin flounder Verasper moseri possesses three POMC mRNAs. In this study, we determined the amino acid sequences of POMC-A, POMC-B, and POMC-C in this fish and investigated the effects of black or white background on the expression of these genes. The three POMC genes (POMCs) were composed of three exons and two introns, wherein all the hormonal segments were encoded on the third exon, a pattern similar to that in other vertebrates. Intron B of POMC-A and POMC-B contained microsatellites of CA repeats, indicating that these two genes diverged from a common immediate ancestor by a recent duplication event. The 5'-flanking regions of the POMC-A (-1051 to -1), POMC-B (-1465 to -1), and POMC-C (-870 to -1) genes contained TATA boxes, Tpit, cyclic AMP response element-like elements, E boxes, and other elements. POMC-B and POMC-C also contained CCAAT boxes. The expression of the three POMCs seems to be regulated by synergistic interactions among a variety of transcription factors. The transfer of barfin flounder between tanks with different colors showed that in response to a black or white background, the expression of these POMCs did not always show similar profiles both in the neurointermediate lobe and pars distalis of the pituitaries. Since these POMCs are expressed in a single cell, the non-synchronous expression of these genes suggests that different sets of transcription factors are associated with the transcription of each gene.
阿黑皮素原（POMC）是促肾上腺皮质激素、促黑素细胞激素和内啡肽的前体。条斑星鲽（Verasper moseri）拥有三种POMC mRNA。在本研究中，我们确定了这种鱼中POMC - A、POMC - B和POMC - C的氨基酸序列，并研究了黑色或白色背景对这些基因表达的影响。这三个POMC基因由三个外显子和两个内含子组成，其中所有激素片段都在第三个外显子上编码，这种模式与其他脊椎动物相似。POMC - A和POMC - B的内含子B含有CA重复的微卫星，表明这两个基因通过最近的复制事件从一个共同的直接祖先分化而来。POMC - A（-1051至-1）、POMC - B（-1465至-1）和POMC - C（-870至-1）基因的5'侧翼区域包含TATA盒、Tpit、环磷酸腺苷反应元件样元件、E盒和其他元件。POMC - B和POMC - C还含有CCAAT盒。这三种POMC的表达似乎受多种转录因子之间协同相互作用的调节。将条斑星鲽转移到不同颜色的水族箱中表明，响应黑色或白色背景，这些POMC在垂体的神经中间叶和远侧部的表达并不总是呈现相似的模式。由于这些POMC在单个细胞中表达，这些基因的非同步表达表明不同的转录因子组合与每个基因的转录相关。
