Jones K W, Shapero M H, Chevrette M, Fournier R E
Department of Molecular Medicine, Fred Hutchinson Cancer Research Center, Seattle, Washington 98104.
Cell. 1991 Sep 6;66(5):861-72. doi: 10.1016/0092-8674(91)90433-y.
Tissue-specific extinguisher 1 (TSE1) is a trans-acting locus on human chromosome 17 that down-regulates expression of seven liver genes in hepatoma x fibroblast hybrids. To study the mechanism by which TSE1 functions, we used subtractive cDNA hybridization to clone transcripts encoded within a 2-4 Mb segment of chromosome 17 that includes TSE1. High resolution mapping within this region indicated that 8 of 9 different human cDNAs so obtained were distinct from TSE1. The remaining cDNA clone mapped concordantly with TSE1 in a panel of fragment-containing hybrids. DNA sequencing indicated that this cDNA encoded regulatory subunit RI alpha of cAMP-dependent protein kinase, and RI alpha mRNA levels correlated with TSE1 activity in various hybrid lines. Stable transfection of wild-type or cAMP-binding mutant RI alpha alleles into hepatoma recipients produced an extinction phenotype indistinguishable from that encoded by human TSE1. We conclude that TSE1 encodes a regulatory subunit of protein kinase A whose activity differs in different cell types.
组织特异性抑制因子1（TSE1）是人类17号染色体上的一个反式作用位点，它可下调肝癌细胞与成纤维细胞杂交体中7种肝脏基因的表达。为了研究TSE1发挥作用的机制，我们利用消减cDNA杂交技术克隆了17号染色体上一个包含TSE1的2 - 4 Mb片段内编码的转录本。该区域内的高分辨率定位表明，如此获得的9种不同人类cDNA中有8种与TSE1不同。其余的cDNA克隆在一组含片段的杂交体中与TSE1共定位。DNA测序表明，该cDNA编码cAMP依赖性蛋白激酶的调节亚基RIα，并且RIα mRNA水平与各种杂交系中的TSE1活性相关。将野生型或cAMP结合突变型RIα等位基因稳定转染至肝癌受体中，产生了与人类TSE1编码的抑制表型无法区分的表型。我们得出结论，TSE1编码蛋白激酶A的一个调节亚基，其活性在不同细胞类型中有所不同。
