Saari J C, Champer R J, Asson-Batres M A, Garwin G G, Huang J, Crabb J W, Milam A H
Department of Ophthalmology, University of Washington, Seattle 98195, USA.
Vis Neurosci. 1995 Mar-Apr;12(2):263-72. doi: 10.1017/s095252380000794x.
An enzyme of bovine retina that catalyzes oxidation of retinaldehyde to retinoic acid was purified to homogeneity and a monoclonal antibody (mAb H-4) was generated. MAb H-4 recognized a single component (Mr = 55,000) in extracts of bovine retina and other bovine tissues. The antibody showed no cross-reactivity with extracts of rat, monkey, or human retinas. A 2067 bp cDNA was selected from a retina cDNA expression library using mAb H-4. The cDNA hybridized with a similarly sized, moderately abundant mRNA prepared from bovine retina. Nucleotide sequence analysis indicated that the cDNA contained a single open reading frame encoding 501 amino acids that have 88% sequence identity with the amino-acid sequence of human hepatic Class 1 aldehyde dehydrogenase. Amino-acid sequence analysis of purified enzyme demonstrated that the cDNA encodes the isolated enzyme. MAb H-4 specifically labeled the somata and processes of a subset of amacrine cells in bovine retinal sections. Labeled amacrine somata were located on both sides of the inner plexiform layer, and their processes ramified into two laminae within the inner plexiform layer. The inner radial processes of Müller (glial) cells were weakly reactive with mAb H-4. Weak immunostaining of amacrine cells was found in monkey retina with mAb H-4, but no signal was detected in rat or human retina. The results provide further evidence for metabolism and function of retinoids within cells of the inner retina and define a novel class of retinal amacrine cells.
一种催化视黄醛氧化为视黄酸的牛视网膜酶被纯化至同质，并产生了一种单克隆抗体（mAb H-4）。mAb H-4识别牛视网膜和其他牛组织提取物中的单一成分（Mr = 55,000）。该抗体与大鼠、猴或人类视网膜提取物无交叉反应。使用mAb H-4从视网膜cDNA表达文库中筛选出一个2067 bp的cDNA。该cDNA与从牛视网膜制备的大小相似、丰度适中的mRNA杂交。核苷酸序列分析表明，该cDNA包含一个单一的开放阅读框，编码501个氨基酸，与人肝1类醛脱氢酶的氨基酸序列具有88%的序列同一性。纯化酶的氨基酸序列分析表明，该cDNA编码分离出的酶。mAb H-4特异性标记牛视网膜切片中一部分无长突细胞的胞体和突起。标记的无长突细胞胞体位于内网状层两侧，其突起在内网状层内分成两层。Müller（神经胶质）细胞的内放射状突起与mAb H-4呈弱阳性反应。在猴视网膜中用mAb H-4发现无长突细胞有弱免疫染色，但在大鼠或人类视网膜中未检测到信号。这些结果为内视网膜细胞中类视黄醇的代谢和功能提供了进一步证据，并定义了一类新型的视网膜无长突细胞。
