Blom T, Hellman L
Department of Immunology, Biomedicum, University of Uppsala, Sweden.
Scand J Immunol. 1993 Feb;37(2):203-8. doi: 10.1111/j.1365-3083.1993.tb01757.x.
The expression of a tryptic serine protease was detected in the cell line KU812 by Northern blot analysis with an oligonucleotide probe directed against a conserved region present in all of the five presently cloned human mast cell tryptases. PCR primers designed for the amplification of a nearly full-length copy of tryptase mRNAs were used to study the identity of the KU812 tryptase. Ten clones were characterized and all were found to be identical to one of the tryptases previously cloned from a human skin cDNA library. This tryptase has been thought to originate from mast cells of the skin. Two possible explanations may account for the observed identity between the presumed mast cell tryptase and the KU812 tryptase. Firstly, it is possible that the KU812 tryptase is a basophil-specific tryptase which has previously been cloned from a human skin cDNA library containing low levels of cDNA copies derived from basophils in the starting material. Secondly, the KU812 cell line, and possibly normal basophils, express a tryptase which is identical to one of the tryptases expressed in normal skin mast cells. We cannot at present rule out any of the two possibilities, but we favour the second explanation as being the most likely.
通过Northern印迹分析，使用针对目前已克隆的5种人类肥大细胞类胰蛋白酶中所有保守区域的寡核苷酸探针，在KU812细胞系中检测到一种胰蛋白酶丝氨酸蛋白酶的表达。为扩增类胰蛋白酶mRNA的几乎全长拷贝而设计的PCR引物，用于研究KU812类胰蛋白酶的特性。对10个克隆进行了鉴定，发现它们均与先前从人皮肤cDNA文库中克隆的一种类胰蛋白酶相同。这种类胰蛋白酶被认为起源于皮肤肥大细胞。对于假定的肥大细胞类胰蛋白酶与KU812类胰蛋白酶之间观察到的一致性，可能有两种解释。首先，有可能KU812类胰蛋白酶是一种嗜碱性粒细胞特异性类胰蛋白酶，它先前是从一个起始材料中含有低水平源自嗜碱性粒细胞的cDNA拷贝的人皮肤cDNA文库中克隆出来的。其次，KU812细胞系，可能还有正常嗜碱性粒细胞，表达一种与正常皮肤肥大细胞中表达的一种类胰蛋白酶相同的类胰蛋白酶。目前我们无法排除这两种可能性中的任何一种，但我们更倾向于第二种解释，认为它最有可能。
