Huppi K, Siwarski D
Molecular Genetics Section, NCI/NIH, Bethesda, MD 20892.
Int J Cancer. 1994 Dec 15;59(6):848-51. doi: 10.1002/ijc.2910590623.
Some mouse plasmacytomas exhibit a t(6;15) chromosomal translocation in which the breakpoint resides within the Pvt-1 locus located 260 kilobases (kb) downstream of c-myc on mouse chromosome 15. In this report, we show that the Pvt-1 locus does not exhibit allelic exclusion in that Pvt-1 transcripts continue to be expressed from the non-translocated allele in t(6;15) plasmacytomas. From the translocated allele, we find chimeric transcripts containing a short 57-bp segment of Pvt-1 (termed Pvt-1a) spliced directly to the immunoglobulin constant region sequence (Ig-Ck). These short transcripts have replaced a Jk segment with a trytophan residue via RNA splicing and contain a continuous open reading frame (ORF) from Pvt-1a through Ck. Since this Pvt-1a/Ck transcript is found in all 3 t(6;15) plasmacytomas examined, regardless of the location of the chromosomal breakpoint, we suggest that the Pvt-1a/Ck chimera may have a functional role in the development of mouse plasmacytomas.
一些小鼠浆细胞瘤表现出t(6;15)染色体易位，其断点位于小鼠15号染色体上c-myc下游260千碱基(kb)处的Pvt-1基因座内。在本报告中，我们表明Pvt-1基因座不表现出等位基因排斥，因为在t(6;15)浆细胞瘤中，Pvt-1转录本继续从非易位等位基因表达。从易位等位基因中，我们发现嵌合转录本，其包含一段57 bp的短Pvt-1片段(称为Pvt-1a)，直接剪接到免疫球蛋白恒定区序列(Ig-Ck)。这些短转录本通过RNA剪接用一个色氨酸残基取代了一个Jk片段，并包含一个从Pvt-1a到Ck的连续开放阅读框(ORF)。由于在所有检测的3个t(6;15)浆细胞瘤中都发现了这种Pvt-1a/Ck转录本，无论染色体断点的位置如何，我们认为Pvt-1a/Ck嵌合体可能在小鼠浆细胞瘤的发生发展中具有功能作用。
