Magyar A, Bakos E, Váradi A
Institute of Enzymology, Biological Research Centre, Hungarian Academy of Sciences, Budapest.
Biochem J. 1995 Sep 15;310 ( Pt 3)(Pt 3):757-63. doi: 10.1042/bj3100757.
A 14 kb genomic clone covering the organellar-type Ca(2+)-ATPase gene of Drosophila melanogaster has been isolated and characterized. The sequence of a 7132 bp region extending from 1.1 kb 5' upstream of the initiation ATG codon over the polyadenylation signal at the 3' end has been determined. The gene consists of nine exons including one with an exceptional size of 2172 bp representing 72% of the protein coding region. Introns are relatively small (< 100 bp) except for the 3' intron which has a size of 2239 bp, an exceptionally large size among Drosophila introns. Five of the introns are in the same positions in Drosophila, Artemia and rabbit SERCA1 Ca(2+)-ATPase genes. There is only one organellar-type Ca(2+)-ATPase gene in the Drosophila genome, as was shown by Southern-blot analysis [Váradi, Gilmore-Hebert and Benz (1989) FEBS Lett. 258, 203-207] and by chromosomal localization [Magyar and Váradi (1990) Biochem. Biophys. Res. Commun. 173, 872-877]. Primer extension and S1-nuclease assays revealed a potential transcription initiation site 876 bp upstream of the translation initiation ATG with a TATA-box 23 bp upstream of this site. Analysis of the 5' region of the Drosophila organellar-type Ca(2+)-ATPase gene suggests the presence of potential recognition sequences of various muscle-specific transcription factors and shows a region with remarkable similarity to that in the rabbit SERCA2 gene. The tissue distribution of expression of the organellar-type Ca(2+)-ATPase gene has been studied by in situ RNA-RNA hybridization on microscopic sections. A low mRNA abundance can be detected in each tissue of adult flies, suggesting a housekeeping function for the gene. On the other hand a pronounced tissue specificity of expression has also been found as the organellar-type Ca(2+)-ATPase is expressed at a very high level in cell bodies of the central nervous system and in various muscles.
已分离并鉴定出一个覆盖黑腹果蝇细胞器型钙ATP酶基因的14 kb基因组克隆。测定了从起始ATG密码子上游1.1 kb处延伸至3'端多聚腺苷酸化信号的7132 bp区域的序列。该基因由9个外显子组成，其中一个外显子大小异常，为2172 bp，占蛋白质编码区的72%。除3'内含子大小为2239 bp（在果蝇内含子中异常大）外，内含子相对较小（<100 bp）。其中5个内含子在果蝇、卤虫和兔SERCA1钙ATP酶基因中的位置相同。如Southern杂交分析[瓦拉迪、吉尔摩 - 赫伯特和本兹（1989年）《欧洲生物化学学会联合会快报》258，203 - 207]及染色体定位[马加尔和瓦拉迪（1990年）《生物化学与生物物理研究通讯》173，872 - 877]所示，果蝇基因组中仅存在一个细胞器型钙ATP酶基因。引物延伸和S1核酸酶分析揭示了一个潜在转录起始位点，位于翻译起始ATG上游876 bp处，其上游23 bp处有一个TATA框。对果蝇细胞器型钙ATP酶基因5'区域的分析表明存在各种肌肉特异性转录因子的潜在识别序列，并显示出与兔SERCA2基因中该区域具有显著相似性的区域。通过在显微切片上进行原位RNA - RNA杂交研究了细胞器型钙ATP酶基因表达的组织分布。在成年果蝇的每个组织中均可检测到低水平的mRNA丰度，表明该基因具有管家功能。另一方面，也发现了明显的组织特异性表达，因为细胞器型钙ATP酶在中枢神经系统的细胞体和各种肌肉中高水平表达。
