Cloning of responsible genes causing myelodysplasia in myelodysplastic syndrome

用13个粘粒探针进行FISH（tel-FB 12-CA 5-G7-FD 2-CB 1-ED 8-FD 9-G32-AE 3-G50-AD 8-GG 4-PEBP 2_C--cen），我们确定了t（1 ; 3）的1 p36断裂点。4例骨髓增生异常综合征（MDS）患者和1例成人型CML患者中的p36 ; q21易位：4例MDS患者的断点位于CA 5和G7之间（1p36.3），CML患者的断点位于GG 4-PEBP 2 αC之间（1p36.1）。这表明1 p36断裂点在不同疾病之间是不同的。作为下一步，我们使用总共33个BAC克隆制作了CA 5和G7之间的重叠群图谱。3例MDS患者的断裂点位于PAC 163 G9克隆，1例MDS患者的断裂点位于BAC 737 N8克隆，提示MDS患者的1 p36断裂点最多分散在340 kb区域内，而BAC克隆一般覆盖170 kb左右。现在，我们正在通过DNA测序搜索这两个克隆中包含的所有基因，以找到MDS的相关基因。另一方面，Mochizuki等人报道，他们找到了t（1 ; 3）的相关基因。（p36 ; q21）易位（Mochizuki N等人：一种新的基因，MEL 1，定位于1p36.3，与MDS/EVI 1基因高度同源，并在t（1 ; 3）中转录激活）（p36 ; q21）阳性白血病细胞。第96章：3209，2000）：仅在t（1 ; 3）（p36 ; q21）阳性白血病细胞中，位于1 p36断裂点附近的MEL 1基因被位于3q 21断裂点附近的Evi 1基因的启动子转录激活。我们还研究了MEL 1基因是否在我们系列的两个MDS患者中表达。我们发现PRDM 16基因而不是MEL 1基因被高度表达，该基因显示出与MEL 1的高度同源性，仅在3'末端有差异，尽管该基因在任何其他细胞系中不表达（制备中）。

Using FISH with 13 cosmid probes (tel--FB12-CA5-G7-FD2- CB1 -ED8-FD9-G32-AE3-G50-AD8-GG4-PEBP2_C--cen), we have determined the 1p36 breakpoint of t(1 ; 3)(p36 ; q21) translocation in four myelodysplastic syndrome (MDS) patients and one adult-type CML patient : the breakpoint was between CA5 and G7 (1p36.3) in four MDS patients and between GG4-PEBP2αC (1p36.1) in the CML patient. This indicated that the 1p36 breakpoint was different between different disorders. As a next step, we made a contig map between CA5 and G7 using a total of 33 BAC clones. The breakpoints of three MDS patients were found in PAC163G9 clone, and that of the remaining MDS patient was found in BAC737N8, suggesting that the 1p36 breakpoint in MDS may be scattered in 340 kb region at most, since BAC clone generally cover ca 170kb. Now, we are searching all the genes contained in the two clones through DNA sequencing to find out the responsible gene for MDS.On the other hand, Mochizuki, et al. reported that they found out responsible genes for t(1 ; 3)(p36 ; q21) translocation (Mochizuki N, et al : A novel gene, MEL1, mapped to 1p36.3 is highly homologous to the MDS/EVI1 gene and is transcriptionally activated in t(1 ; 3)(p36 ; q21)-positive leukemia cells. Blood 96 : 3209, 2000) : MEL1 gene located adjacent to the 1p36 breakpoint was transcriptionally activated by the promoter of Evi1 gene located adjacent to the 3q21 breakpoint only in t(1 ; 3)(p36 ; q21)-positive leukemia cells. We also studied whether the MEL1 gene was expressed in two MDS patients of our series. We found that PRDM16 gene, not MEL1, which shows highly homology to MEL1 with only difference in 3' end was highly expressed although this gene was not expressed in any other cell lines (in preparation).