Wei L N, Mertz J R, Goodman D S, Nguyen-Huu M C
Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, New York 10032.
Mol Endocrinol. 1987 Aug;1(8):526-34. doi: 10.1210/mend-1-8-526.
Both cellular retinoic acid-binding protein (CRABP) and cellular retinol-binding protein (CRBP) are widely distributed in mammalian tissues and display different patterns of tissue distribution. We have isolated cDNA clones for bovine CRABP and for human CRBP from a bovine adrenal gland cDNA library and from a human liver cDNA library, respectively, by probing with synthetic oligonucleotides. The primary structures of the two proteins inferred from the DNA sequences were identical to the previously reported amino acid sequences. The cDNA probes were used to obtain some information about the genes for CRABP and CRBP, including their chromosomal localization, and about the tissue specific expression of these two genes. Southern blot analyses under highly stringent conditions, of genomic DNA from both the bovine and the mouse, showed that for each retinoid-binding protein, specific DNA sequences are sufficiently conserved across species to allow cross-hybridization to occur. Under the same conditions, however, the DNA sequences for CRABP and CRBP within each species appear to be sufficiently different that cross-hybridization was not observed between the two cDNA probes. Using mouse-hamster somatic cell hybrids, it was demonstrated that these genes map to mouse chromosome 9 or 10. Northern blot analyses of RNA from six tissues from both the bovine and the mouse showed marked differences in the levels of the specific transcript for each binding protein among the different tissues, and in the tissue distribution of CRABP mRNA as compared to that of CRBP mRNA. In both species, CRBP mRNA was detected in more tissues than was CRABP mRNA. For both proteins, the relative tissue distribution of the mRNAs appeared to both resemble and to differ from the reported distribution of the binding proteins themselves. The factors that regulate the tissue specific expression of the genes for CRABP and CRBP remain to be determined.
细胞视黄酸结合蛋白（CRABP）和细胞视黄醇结合蛋白（CRBP）在哺乳动物组织中广泛分布，并呈现出不同的组织分布模式。我们分别从牛肾上腺cDNA文库和人肝脏cDNA文库中，通过用合成寡核苷酸进行探针杂交，分离出了牛CRABP和人CRBP的cDNA克隆。从DNA序列推断出的这两种蛋白质的一级结构与先前报道的氨基酸序列相同。这些cDNA探针被用于获取有关CRABP和CRBP基因的一些信息，包括它们的染色体定位，以及这两个基因的组织特异性表达情况。在高度严格条件下对牛和小鼠的基因组DNA进行Southern印迹分析表明，对于每种类维生素A结合蛋白，特定的DNA序列在物种间具有足够的保守性，能够发生交叉杂交。然而，在相同条件下，每个物种内CRABP和CRBP的DNA序列似乎差异足够大，以至于在这两种cDNA探针之间未观察到交叉杂交。利用小鼠 - 仓鼠体细胞杂种，证明这些基因定位于小鼠的9号或10号染色体。对牛和小鼠的六种组织的RNA进行Northern印迹分析表明，不同组织中每种结合蛋白的特异性转录本水平存在显著差异，并且与CRBP mRNA相比，CRABP mRNA的组织分布也有所不同。在这两个物种中，检测到CRBP mRNA的组织比CRABP mRNA更多。对于这两种蛋白质，mRNA的相对组织分布似乎既类似于又不同于所报道的结合蛋白本身的分布。调节CRABP和CRBP基因组织特异性表达的因素仍有待确定。
