Kallam Anji Reddy Molecular Genetics Laboratory, Hyderabad Eye Research Foundation, LV Prasad Eye Institute, Hyderabad 500034, India.
J Biosci. 2011 Jun;36(2):281-7. doi: 10.1007/s12038-011-9062-9.
Analysis of RB1 mRNA from blood leukocytes of patients with retinoblastoma identified the effects of mutations involving consensus splice site, exonic substitution and whole-exon deletions identified in genomic DNA of these patients. In addition, this study identified mutations in cases in which no mutations were detectable in the genomic DNA. One proband had mutation at the canonical splice site at +5 position of IVS22, and analysis of the transcripts in this family revealed skipping of exon 22 in three members of this family. In one proband, a missense substitution of c.652T greater than G (g.56897T greater than G; Leu218Val) in exon 7 led to splicing aberrations involving deletions of exons 7 and 8, suggesting the formation of a cryptic splice site. In two probands with no detectable changes in the genomic DNA upon screening of RB1 exons and flanking intronic sequences, transcripts were found to have deletions of exon 6 in one, and exons 21 and 22 in another family. In two probands, RNA analysis confirmed genomic deletions involving one or more exons. This study reveals novel effects of RB1 mutations on splicing and suggests the utility of RNA analysis as an adjunct to mutational screening of genomic DNA in retinoblastoma.
从患有视网膜母细胞瘤的患者的血液白细胞中分析 RB1 mRNA，鉴定出这些患者的基因组 DNA 中涉及共识剪接位点、外显子取代和外显子缺失的突变的影响。此外，这项研究还鉴定了在基因组 DNA 中未检测到突变的病例中的突变。一个先证者在 IVS22 的+5 位置的经典剪接位点发生突变，对这个家族的转录本进行分析显示，该家族的三个成员中存在外显子 22 的跳跃。在一个先证者中，外显子 7 中的 c.652T 大于 G 错义取代（g.56897T 大于 G；Leu218Val）导致涉及外显子 7 和 8 缺失的剪接异常，提示形成了一个隐蔽的剪接位点。在两个先证者中，在 RB1 外显子和侧翼内含子序列的筛查中未发现基因组 DNA 的可检测变化，发现一个家族的转录本存在外显子 6 的缺失，另一个家族的转录本存在外显子 21 和 22 的缺失。在两个先证者中，RNA 分析证实存在涉及一个或多个外显子的基因组缺失。这项研究揭示了 RB1 突变对剪接的新影响，并表明 RNA 分析作为基因组 DNA 突变筛查的辅助手段在视网膜母细胞瘤中的应用价值。
