Burg M G, Sarthy P V, Koliantz G, Pak W L
Department of Biological Sciences, Purdue University, West Lafayette, IN 47907.
EMBO J. 1993 Mar;12(3):911-9. doi: 10.1002/j.1460-2075.1993.tb05732.x.
Drosophila mutants of a single complementation group with defective on-/off-transients of the electroretinogram (ERG) were found to be deficient in synthesis of the photoreceptor transmitter, histamine, in a gene-dosage dependent manner, suggesting that the gene identified by the mutants (hdc) might be the structural gene for Drosophila histidine decarboxylase (HDC). A rat HDC cDNA was used to isolate a Drosophila homolog which shows approximately 60% sequence identity with mammalian HDCs over a region of 476 amino acids. In RNA blots, the Drosophila homolog detects four transcripts that are expressed primarily in the eye and are severely reduced in hdc mutants. The cloned Drosophila cDNA hybridizes to the 46F region of the chromosome, to which hdc mutations have been mapped, and rescues the hdc mutant phenotype in transgenic flies generated by P element-mediated germline transformation. The results thus show that the Drosophila homolog corresponds to the histidine decarboxylase gene, identified by the hdc mutants, and that mutations in the gene disrupt photoreceptor synaptic transmission.
在一个互补群中，视网膜电图（ERG）的开/关瞬态有缺陷的果蝇突变体被发现以基因剂量依赖的方式在光感受器递质组胺的合成上存在缺陷，这表明由这些突变体鉴定出的基因（hdc）可能是果蝇组氨酸脱羧酶（HDC）的结构基因。使用大鼠HDC cDNA分离出一个果蝇同源物，该同源物在476个氨基酸的区域内与哺乳动物HDCs显示出约60%的序列同一性。在RNA印迹中，果蝇同源物检测到四种主要在眼睛中表达且在hdc突变体中严重减少的转录本。克隆的果蝇cDNA与已定位hdc突变的染色体46F区域杂交，并在P元件介导的种系转化产生的转基因果蝇中拯救了hdc突变体表型。因此，结果表明果蝇同源物对应于由hdc突变体鉴定出的组氨酸脱羧酶基因，并且该基因中的突变破坏了光感受器突触传递。
