Ing Y L, Leung I W, Heng H H, Tsui L C, Lassam N J
Department of Clinical Biochemistry, University of Toronto, Ontario.
Oncogene. 1994 Jun;9(6):1745-50.
We have identified a novel protein kinase, designated MLK-3, from human thymus using RT-PCR and cDNA library screening. The deduced open reading frame, derived from sequencing a 3.5 kb MLK-3 cDNA, encodes a protein of 847 amino acids with several interesting structural features. These include an SH3 domain in the absence of an SH2 domain, a region containing two leucine zippers with an adjacent carboxy-terminal basic region, and a proline rich region. This kinase shows homology with the mixed-lineage family of protein kinases (MLK) and shares the unusual leucine zipper-basic motif found in previously identified MLK kinases. By northern analysis, MLK-3 mRNA was detected in a wide variety of normal and transformed human cell lines and tissue specimens. The gene encoding MLK-3 has been mapped using fluorescence in situ hybridization to human chromosome 11 q13.1-13.3, a region frequently altered in human malignancies.
我们利用逆转录聚合酶链反应（RT-PCR）和cDNA文库筛选技术，从人胸腺中鉴定出一种新型蛋白激酶，命名为MLK-3。通过对一个3.5 kb的MLK-3 cDNA进行测序推导得到的开放阅读框，编码一个含有847个氨基酸的蛋白质，该蛋白质具有几个有趣的结构特征。这些特征包括一个没有SH2结构域的SH3结构域、一个含有两个亮氨酸拉链且相邻羧基末端有碱性区域的区域以及一个富含脯氨酸的区域。这种激酶与蛋白激酶的混合谱系家族（MLK）具有同源性，并具有先前鉴定的MLK激酶中发现的不寻常的亮氨酸拉链-碱性基序。通过Northern分析，在多种正常和转化的人类细胞系及组织标本中检测到了MLK-3 mRNA。利用荧光原位杂交技术，已将编码MLK-3的基因定位到人类染色体1q13.1-13.3，该区域在人类恶性肿瘤中经常发生改变。
