Alternative splicing of the FMR1 gene in human fetal brain neurons

The alternative splicing expression of the FMR1 gene was reported in several human and mouse tissues. Five regions of FMR1 gene can be alternatively spliced, but the combination of them has not been investigated fully. We reported here the analysis of alternative splicing pattern of the FMR1 gene in cultured fetal human neurons, using a RT-PCR and cloning strategy. Eleven splicing types were cloned and different isoforms were not equally represented. The dominant isoform represents nearly 40%, and the other isoforms were relatively rare. One isoform has a different carboxyl-terminus. Most of the alternative spliced regions appear hydrophilic; thus, they may locate on the surface of the FMR1 protein. © 1996 Wiley-Liss, Inc.     

Stage-specific alternative cplicing of CD44 and alpha 6 beta 1 integrin in colorectal tumorigenesis

Recent reports suggest that cancerogenesis induces changes in alternative processing of human genes. However, little is known about the regulation of alternative splicing during malignant transformation. Therefore, we examined changes in alternative splicing of two different adhesion molecules, alpha 6 beta 1 integrin and CD44, in multiple stages of colon tumorigenesis. Using semiquantitative RT-PCR it is shown that the alternatively spliced isoforms of both adhesion molecules, alpha 6A and -B and CD44v6, are significantly upregulated in colorectal adenoma (n = 20) compared to normal colon mucosa (n = 32) (P < 0.01). Although beta1 isoforms were expressed in almost all tissues, there was a significant increase in the intensity of gene expression of beta 1A compared to beta 1B (P <0.05) in adenoma tissue. Interestingly, CD44v6 and alpha 6 variant isoforms were downregulated in carcinoma tissue (n = 28) compared to adenoma. These results establish a link between neoplastic transformation and alternative splicing of cell adhesion molecules. Furthermore, these data suggest that colon epithelial cells carrying splice variants of adhesion molecules might acquire a selective growth advantage during early tumorigenesis.     

K562细胞DHRS4 L1基因新选择性剪接亚型的克隆及二级结构预测

目的： K562细胞DHRS4L1[ dehydrogenase／reductase （ SDR family） member 4 like 1]的表达及其二级结构分析。方法以K562细胞cDNA为模板, PCR扩增DHRS4[ dehydrogenase／reductase （ SDR fami-ly） member 4]基因簇Ea2转录本。将PCR产物A-T克隆至pGEMT-Easy质粒,对质粒进行DNA Sanger测序。将测序所得序列用NCBI ORF finder分析是否存在编码区,用Clustal Omega分析RNA序列系统树,用RNAfold web server分析RNA最小自由能二级结构。结果用RT-PCR和Sanger测序方法发现, K562表达DHRS4L1 Ea2转录本,未检测到其表达DHRS4L2[dehydrogenase／reductase （SDR family） member 4 like 2] Ea1转录本。 K562表达的DHRS4L1 Ea2至少有8种选择性剪接亚型（ KU058702、 KU058703、 KU058704、KU058705、 KU058706、 KU058707、 KU058708、 KU058709）,其中6种为首次发现。 KU058702、 KU058703、KU058704、 KU058705和KU058707第二外显子受到多种形式的选择性剪接,恰好仅影响第2臂的二级结构,不影响其他臂的二级结构,提示这些不同亚型的二级结构有一定相似性,第二外显子所对应的二级结构臂可能在区分不同 DHRS4L1亚型功能中发挥关键作用。结论研究发现 K562细胞至少表达8种DHRS4L1选择性剪接亚型,为长链非编码RNA。其二级结构分析为后续研究DHRS4L1在白血病细胞中的潜在功能奠定基础。