Molecular and biochemical characterization of the aaNAT1 (Dat) locus in Drosophila melanogaster:: Differential expression of two gene products
Molecular and biochemical characterization of the aaNAT1 (Dat) locus in Drosophila melanogaster:: Differential expression of two gene products
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DOI：
10.1089/dna.1998.17.621
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发表时间：
1998-07-01
影响因子：
3.1
通讯作者：
Affolter, M
中科院分区：
文献类型：
--
作者：
Brodbeck, D;Amherd, R;Affolter, M
在昆虫中，芳基烷基胺n -乙酰转移酶（AANATs）参与了几个生理过程，包括硬化、某些神经递质的失活，以及类似于脊椎动物的功能，在褪黑素生物合成中催化限速步骤。在此，我们对黑腹果蝇aaNAT1基因的产物进行了广泛的生化和功能分析，aaNAT1基因通过不同的第一外显子使用产生两个转录本，这些转录本受组织特异性和发育控制，编码的蛋白质的n端与起始蛋氨酸不同，更丰富的同种异构体AANAT1b在胚胎发育晚期在大脑，腹侧神经索，还有中肠；在成人中，AANAT1b在大脑和中肠中仍可检测到，较少的异构体AANAT1a仅在蛹期晚期出现，在成人中主要存在于大脑中。我们证明突变Dat（lo）代表aaNAT1b的一个亚形态等位基因，其中两个转座元件MDG412和囊胚在该基因的第一个内含子内插入。利用去除aaNAT1基因的缺陷，我们提供了aaNAT1在硬化过程中不是必需的证据，此外，这两种酶同型体都没有表现出RNA或蛋白质水平的昼夜调节。AANAT1a和AANAT1b的不同丰度水平和不同的发育控制表明这两种酶在体内的功能不同。
In insects, arylalkylamine N-acetyltransferases (AANATs) have been implicated in several physiological processes, including sclerotization, inactivation of certain neurotransmitters, and, similar to the function in vertebrates, catalysis of the rate-limiting step in melatonin biosynthesis. Here, we report an extensive biochemical and functional analysis of the products of the aaNAT1 gene of Drosophila melanogaster, The aaNAT1 gene generates two transcripts through alternative first-exon usage, These transcripts are under tissue-specific and developmental control and encode proteins which differ in their N-terminus with respect to their starting methionine, The more abundant isoform, AANAT1b, is first expressed during late embryogenesis in the brain, the ventral nerve cord, and the midgut; in adults, AANAT1b is still detectable in the brain and midgut, The less abundant isoform, AANAT1a, appears only during late pupal stages and in adults is found predominantly in the brain. We demonstrate that the mutation Dat(lo) represents a hypomorphic allele of aaNAT1b, in which an insertion of two transposable elements, MDG412 and blastopia, has occurred within the first intron of the gene, Using a deficiency which removes the aaNAT1 gene, we provide evidence that aaNAT1 is not essential for the process of sclerotization, Furthermore, neither of the two enzyme isoforms shows circadian regulation of RNA or protein levels. The differing levels of abundance and distinct developmental control of AANAT1a and AANAT1b suggest different in vivo functions for these two enzymes.