Effect of poly(ADP-ribose) synthetase on the expression of MHC class II molecules.

我们已经证明，高表达的聚（ADP-核糖）合成酶（PARS）引起的抑制MHC II类分子。在组成型表达MHC Ⅱ类分子的B细胞系中，存在大量的PARS，因此，我们试图检测与PARS相互作用并调节MHC Ⅱ类基因的细胞类型特异性反式作用因子<35><35>。我们在B细胞中检测到PARS的45 kDa和35 kDa的结合伴侣。II.我们在DNase I超敏位点II（DHS II）区域制备了人MHC II类基因组DNA的探针DNA。我们从II类阳性细胞、II类诱导细胞和阴性细胞制备核蛋白，并通过使用DHS II DNA探针的South-western印迹法对其进行分析。我们检测到一个35 kDa的核蛋白与DNA探针相互作用。DHS II相关的35 kDa蛋白是否与PARS相互作用仍在研究中。

We have demonstrated that the high expression of poly (ADP-ribose) synthetase (PARS) caused the depression of MHC class II molecules. In B cell lines, which constitutively express the class II molecule, there are significant amounts of PARS.Thus, we attempted to detect a cell type-specific trans-acting factor which interacted with PARS and regulated the MHC class II gene.I.We constructed a fusion protein by using the automodification and DNA binding domains of PARS.We labeled nuclear proteins with ^<35>S-Met in B cells and macrophage cells and the ^<35>S-labeled nuclear proteins were incubated with the PARS-fusion protein. We detected a 45kDa and 35kDa binding partner for PARS in B cells.II.We prepared a probe DNA of human MHC class II genomic DNA in the region of DNase I hypersensitive site II(DHSII). We prepared nuclear proteins from class II-positive cells, class II-inducible cells and negative cells and analyzed them by South-western blotting by the use of the DHS II DNA probe. We detected a 35kDa nuclear protein which interacted with the DNA probe. Whether or not the DHS II-associated 35kDa protein interacts with PARS is still under investigation.