Wright P S, Carlson D M
Department of Biochemistry and Biophysics, University of California, Davis 95616.
FASEB J. 1988 Dec;2(15):3104-7. doi: 10.1096/fasebj.2.15.2847950.
Salivary proline-rich proteins are encoded by tissue-specific multigene families, and are dramatically induced in mice, rats, and hamsters by treatment with the beta agonist isoproterenol. Salivary gland cells, however, are difficult to maintain in a differentiated state in culture and can be induced to synthesize proline-rich protein mRNAs for only a few days. In an attempt to establish a cell line in which it would be possible to regulate proline-rich protein gene transcription, rat parotid gland cells were fused with the rat hepatoma cell line, FTO-2B. Fused cells were obtained that had a frequency of 7.5 x 10(-6), which is about 125-fold greater than the reversion rate of FTO-2B. The hybrid cells exhibited induced proline-rich protein mRNA synthesis when incubated with either dibutyryl cyclic AMP or forskolin. The ability to induce these genes was maintained for at least 20 passages. Most of the fused cell populations also synthesized elevated levels of alpha-amylase mRNA, another tissue-specific gene.
富含脯氨酸的唾液蛋白由组织特异性多基因家族编码，在小鼠、大鼠和仓鼠中，用β-激动剂异丙肾上腺素处理后会显著诱导其表达。然而，唾液腺细胞在培养中难以维持分化状态，并且只能在几天内被诱导合成富含脯氨酸的蛋白质mRNA。为了建立一个能够调节富含脯氨酸的蛋白质基因转录的细胞系，将大鼠腮腺细胞与大鼠肝癌细胞系FTO-2B融合。获得了融合细胞，其频率为7.5×10^(-6)，这比FTO-2B的回复率大约高125倍。当与二丁酰环磷腺苷或福斯可林一起孵育时，杂交细胞表现出诱导的富含脯氨酸的蛋白质mRNA合成。诱导这些基因的能力至少维持了20代。大多数融合细胞群体还合成了高水平的α-淀粉酶mRNA，这是另一种组织特异性基因。
