Eisinger D P, Jiang H P, Serrero G
W. Alton Jones Cell Science Center, Inc., Lake Placid, NY 12946.
Biochem Biophys Res Commun. 1993 Nov 15;196(3):1227-32. doi: 10.1006/bbrc.1993.2383.
A cDNA clone referred to as 168 was previously isolated from mouse 1246 adipocytes by differential hybridization on the basis of its down regulation in adipocytes when compared to preadipocytes. 5' RACE was used to obtain a full length clone of 761 bp encoding for a highly basic 25 kD polypeptide that is extremely conserved in several diverse species of eukaryotes. There is a single amino acid substitution at position 202 compared to the human homolog, QM, a putative tumor suppressor. Clone 168 mRNA decreases 80% in rat primary culture of adipocytes compared to preadipocytes and does not decrease when differentiation is blocked by PGF2 alpha or EGF, indicating that the decrease is correlated with expression of the differentiation phenotype. Finally, two 1246 cell line variants that exhibit altered growth and increased tumorigenicity have a similar level of 168 mRNA when compared to the non tumorigenic adipogenic parent cell line.
一个名为168的cDNA克隆先前是从小鼠1246脂肪细胞中通过差异杂交分离出来的，其依据是与前脂肪细胞相比，它在脂肪细胞中表达下调。采用5' RACE技术获得了一个761 bp的全长克隆，该克隆编码一种高度碱性的25 kD多肽，这种多肽在几种不同的真核生物物种中极为保守。与人类同源物QM（一种假定的肿瘤抑制因子）相比，在第202位氨基酸处存在一个单氨基酸替换。与前脂肪细胞相比，克隆168 mRNA在大鼠原代脂肪细胞培养物中减少了80%，并且当分化被前列腺素F2α或表皮生长因子阻断时不减少，这表明这种减少与分化表型的表达相关。最后，与非致瘤性脂肪生成亲本细胞系相比，两个表现出生长改变和致瘤性增加的1246细胞系变体具有相似水平的168 mRNA。
