Chong S S, Tanigami A, Roschke A V, Ledbetter D H
National Center for Human Genome Research, National Institutes of Health, Bethesda, Maryland 20892, USA.
Genome Res. 1996 Aug;6(8):735-41. doi: 10.1101/gr.6.8.735.
Previously, we isolated several cDNA clones of the LIS1 gene implicated in Miller-Dieker syndrome. Analysis of the 5' end of one of the clones (8-1), which was originally thought to represent the 5' end of LIS1, indicates a striking similarity to mouse 14-3-3 epsilon. We have isolated a full-length cDNA of human 14-3-3 epsilon, for which sequence analysis reveals a strong nucleotide conservation with mouse 14-3-3 epsilon in both translated and untranslated regions (UTRs). Additionally, the predicted peptides of human, sheep, rat, and mouse 14-3-3 epsilon are identical. Using a 205-bp fragment common to LIS1 (8-1) and 14-3-3 epsilon as probe on adult and fetal multiple-tissue Northern blots, a -2-kb transcript is detected, identical to the pattern observed with a full-length 14-3-3 epsilon cDNA probe. LIS1-specific transcripts of approximately 7.5 and approximately 5 kb are not detected by the 0.2-kb probe, indicating that the similarity between the 5' sequence of LIS1 (8-1) and the 3' UTR of 14-3-3 epsilon is not the result of shared homology between the two genes. Instead, clone 8-1 is a chimera of 14-3-3 epsilon and LIS1 partial cDNAs, and therefore its 5' sequence does not represent the LIS1 5' end. Interestingly, we have mapped the 14-3-3 epsilon gene to the same chromosomal sub-band as LIS1 (17p13.3). However, 14-3-3 epsilon lies telomeric to LIS1 and outside the Miller-Dieker syndrome chromosome region but in a region frequently deleted in several types of cancer, and is a reasonable candidate tumor suppressor gene.
此前，我们分离出了几个与米勒-迪克尔综合征相关的LIS1基因的cDNA克隆。对其中一个最初被认为代表LIS1 5'端的克隆（8-1）的5'端进行分析，发现其与小鼠14-3-3ε有显著相似性。我们分离出了人14-3-3ε的全长cDNA，序列分析表明，其在编码区和非编码区（UTR）与小鼠14-3-3ε都有很强的核苷酸保守性。此外，人、羊、大鼠和小鼠14-3-3ε的预测肽段是相同的。用LIS1（8-1）和14-3-3ε共有的一个205bp片段作为探针，对成人和胎儿的多组织Northern印迹进行检测，检测到一个-2kb的转录本，与用全长14-3-3ε cDNA探针观察到的模式相同。0.2kb的探针未检测到约7.5kb和约5kb的LIS1特异性转录本，这表明LIS1（8-1）的5'序列与14-3-3ε的3'UTR之间的相似性不是两个基因共享同源性的结果。相反，克隆8-1是14-3-3ε和LIS1部分cDNA的嵌合体，因此其5'序列不代表LIS1的5'端。有趣的是，我们已将14-3-3ε基因定位到与LIS1相同的染色体亚带（17p13.3）。然而，14-3-3ε位于LIS1的端粒侧，在米勒-迪克尔综合征染色体区域之外，但在几种类型癌症中经常缺失的区域，是一个合理的候选肿瘤抑制基因。
