Agape P, Gerard B, Cave H, Devaux I, Vilmer E, Lecomte M C, Grandchamp B
INSERM U409, Faculté de Médecine Bichat, Paris, France.
Br J Haematol. 1997 Jul;98(1):234-9. doi: 10.1046/j.1365-2141.1997.1973014.x.
The t(12;21) is a recurring chromosomal abnormality in acute lymphoblastic leukaemias (ALLs) which results in the production of an ETV6-AML1 fusion gene. The association between t(12;21) and the deletion of the untranslocated allele of ETV6 is among the most frequent abnormalities observed in B-lineage ALLs in children. In order to study the proteins encoded by ETV6 and ETV6-AML1, we raised polyclonal antibodies directed against a recombinant peptide corresponding to the junctional region of ETV6-AML1. Cell lysates from various leukaemic cell lines, and from children with B- and T-lineage ALLs, were studied by Western blot. Two isoforms of ETV6 protein were detected in normal bone marrow cells and in leukaemic cells without 12p alteration: a major form (apparent m.w. 63 kD) and a minor one (apparent m.w. 53 kD). In the REH cell line, which expresses the ETV6-AML1 fusion transcript and no normal ETV6 mRNA, the ETV6 isoforms were absent and two new bands were detected corresponding to ETV6-AML1 protein products (apparent m.w. 95 and 105 kD). A similar pattern was obtained with blast cells from patients with a t(12;21) and a deletion of ETV6. In two patients with a t(12;21) but no deletion of ETV6, four bands were detected corresponding to both the normal ETV6 and ETV6-AML1 proteins, suggesting that in these cases the second ETV6 allele was not inactivated. Surprisingly, the expression pattern of ETV6 differed widely from patient to patient. In three out of 13 patients without t(12;21), the relative intensity of the bands corresponding to ETV6 isoforms in blast cells from patients was completely different from normal cells, with a marked predominance of the 53 kD isoform. The pattern of ETV6 expression was normal in bone marrow from the same patients during remission. These finding suggest that ETV6 abnormalities are not restricted to patients with translocations or deletions involving this gene.
t(12;21)是急性淋巴细胞白血病（ALL）中一种常见的染色体异常，会导致ETV6-AML1融合基因的产生。t(12;21)与ETV6未易位等位基因的缺失之间的关联是儿童B系ALL中最常见的异常之一。为了研究ETV6和ETV6-AML1编码的蛋白质，我们制备了针对与ETV6-AML1连接区域对应的重组肽的多克隆抗体。通过蛋白质印迹法研究了来自各种白血病细胞系以及B系和T系ALL患儿的细胞裂解物。在正常骨髓细胞和无12p改变的白血病细胞中检测到两种ETV6蛋白异构体：一种主要形式（表观分子量63 kD）和一种次要形式（表观分子量53 kD）。在表达ETV6-AML1融合转录本且无正常ETV6 mRNA的REH细胞系中，ETV6异构体缺失，并检测到两条对应于ETV6-AML1蛋白产物的新条带（表观分子量95和105 kD）。对于有t(12;21)且ETV6缺失的患者的原始细胞，也获得了类似的模式。在两名有t(12;21)但无ETV6缺失的患者中，检测到四条对应于正常ETV6和ETV6-AML1蛋白的条带，表明在这些情况下，第二个ETV6等位基因未失活。令人惊讶的是，ETV6的表达模式在患者之间差异很大。在13例无t(12;
