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ｐ５３可以同细胞内的许多种蛋白质形成复合物从而参与细胞周期调节、基因表达调控、细胞分化、细胞程序化死亡和抑制肿瘤的发生等各项生理过程。为了筛选与ｐ５３作用的蛋白质因子，利用酵母双杂交（ｔｗｏ－ｈｙｂｒｉｄ）系统，筛选了ＨｅＬａ细胞的ｃＤＮＡ文库。在１．５×１０６个转化子中筛选到６个阳性克隆。经ＤＮＡ全序列分析，结果表明５个阳性克隆中的ｃＤＮＡ序列编码产物均由１５８个氨基酸构成，分子量为１７ｋＤ的人泛肽交联酶。同源性比较表明，该泛肽交联酶与人的ＵＢＣ９（９７％）、线虫的ＵＢＣ（７６％）、裂殖酵母的ＨＵＳ５（６６％）、拟南芥菜的ＵＢＣ（６６％）和啤酒酵母的ＵＢＣ９（５６％）有较高的同源性。进行了１６种正常人组织和７种肿瘤细胞株的Ｎｏｒｔｈｅｒｎ杂交分析，结果显示：它在心脏、胎盘、胸腺、睾丸、卵巢、结肠和外周血白细胞中的表达较在肝脏、骨骼肌、肾脏、胰腺、脾脏、前列腺和小肠中为高，而在脑和肺中则检测不到表达。它在宫颈癌细胞株、乳腺癌细胞株、淋巴瘤细胞株和畸胎瘤细胞株中的表达较高，而在肺癌细胞株、肝癌细胞株和神经胶质瘤细胞株中则无明显表达。
p53 can complex with many kinds of proteins in the cell to participate in various physiological processes such as cell cycle regulation, gene expression regulation, cell differentiation, programmed cell death and tumor suppression. To screen for protein factors that interact with p53, a HeLa cell cDNA library was screened using a yeast two-hybrid system. Six positive clones were screened from 1.5 × 106 transformants. The DNA sequence analysis showed that the cDNA sequences of the five positive clones encoded human ubiquitin peptide with 158 amino acids and a molecular weight of 17 kD. Homology comparison showed that the ubiquitin-linked enzyme interacts with human UBC9 (97%), nematode UBC (76%), fission yeast HUS5 (66%), Arabidopsis thaliana UBC Yeast UBC9 (56%) has high homology. Northern hybridization analysis of 16 kinds of normal human tissues and 7 kinds of tumor cell lines showed that the expression in heart, placenta, thymus, testis, ovary, colon and peripheral blood leucocytes was significantly higher than that in liver, skeletal muscle, kidney, The pancreas, spleen, prostate and small intestine were high, whereas no expression was detected in the brain and lung. It is highly expressed in cervical cancer cell lines, breast cancer cell lines, lymphoma cell lines and teratoma cell lines, but not in lung cancer cell lines, liver cancer cell lines and glioma cell lines.