The same gamma-glutamyl transpeptidase RNA species is expressed in fetal liver, hepatic carcinomas, and rasT24-transformed rat liver epithelial cells.
The same gamma-glutamyl transpeptidase RNA species is expressed in fetal liver, hepatic carcinomas, and rasT24-transformed rat liver epithelial cells.
复制标题
相同的 γ-谷氨酰转肽酶 RNA 种类在胎儿肝脏、肝癌和 rasT24 转化的大鼠肝上皮细胞中表达。
DOI：
10.1002/mc.2940050112
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发表时间：
1992
影响因子：
4.6
通讯作者：
Lieberman,MW
中科院分区：
文献类型：
--
作者：
Habib,GM;Rajagopalan,S;Godwin,AK;Lebovitz,RM;Lieberman,MW
在大鼠中，γ-谷氨酰转肽酶（γGT）以单拷贝基因形式存在，并且已经鉴定出3种不同的RNA（I、II和III型），它们的5′非翻译区不同。为了比较这些γGT RNA在大鼠组织、肝癌和培养细胞中的稳态水平，我们使用RNA斑点杂交和逆转录酶-聚合酶链反应（RT-PCR）技术，并使用针对每种类型RNA专门设计的寡核苷酸。胎肝、肝癌、rasT 24转化的大鼠肝上皮（RLE）细胞和胰腺仅产生III型RNA。肝脏和未转化的RLE细胞未产生可检测水平的γGT RNA。我们发现，胎儿和成人肾脏都合成所有三种类型的RNA，表明出生后已知发生的γGT RNA增加并不是由于额外RNA种类的募集。当我们通过在额外一轮扩增后直接对RT-PCR产物进行测序将检测的灵敏度提高约1000倍时，我们发现在胎儿肝脏、rasT 24转化的RLE细胞和胰腺中存在非常低水平的I型和II型RNA，并且成人肝脏和未转化的RLE细胞合成非常低水平的所有三种RNA。Rat‐1成纤维细胞无法通过该方法检测到γGT RNA水平。这些结果表明，不同的γGT RNA种类在发育和肿瘤转化过程中受到不同的调节，并且在某些细胞类型中存在γGT RNA极低水平表达的承诺。
In rats, ‐γ‐glutamyl transpeptidase (γGT) exists as a single‐copy gene, and three distinct species of RNA (types I, II, and III) that differ in their 5′ untranslated regions have been identified. To compare steady‐state levels of these ‐γGT RNAs in rat tissues, hepatic carcinomas, and cultured cells, we used RNA dot‐blot hybridization and a reverse transcriptase‐polymerase chain reaction (RT‐PCR) technique with oligonucleotides specifically designed for each type of RNA. Fetal liver, hepatic carcinomas,rasT24‐transformed rat liver epithelial (RLE) cells and pancreas make only type III RNA. Liver and untransformed RLE cells do not make detectable levels of γGT RNA. We found that both fetal and adult kidneys synthesize all three types of RNA, indicating that increases in γGT RNA known to occur after birth do not result from recruitment of additional RNA species. When we increased the sensitivity of the assay approximately 1000 fold by sequencing the RT‐PCR product directly after an additional round of amplification, we found that very low levels of types I and II RNA were present in fetal liver,rasT24‐transformed RLE cells, and pancreas, and that adult liver and untransformed RLE cells synthesized very low levels of all three RNA species. Rat‐1 fibroblasts did not make levels of γGT RNA detectable by this method. These results demonstrate that different γGT RNA species are regulated differently during development and neoplastic transformation and that there is a commitment in some cell types to very‐low‐level expression of γGT RNAs.