Breakpoint cluster regions of the AML-1 and ETO genes contain MAR elements and are preferentially associated with the nuclear matrix in proliferating HEL cells

Abstract

The spatial organization in interphase nuclei of the breakpoint cluster regions (BCRs) of the AML-1 and ETO genes frequently participating in reciprocal t(8;21) translocations was studied using cytological and biochemical approaches. Both BCRs were found to be localized preferentially, but not exclusively, to the nuclear matrix, as shown by hybridization of specific probes with nuclear halos. This association was not related to transcription, because the transcribed regions of both genes located far from BCRs were located preferentially in loop DNA, as shown by in situ hybridization. The sites of association with the nuclear matrix of the intensely transcribed AML-1 gene were mapped also using the biochemical PCR-based approach. Only the BCR was found to be associated with the nuclear matrix, whereas the other transcribed regions of this gene turned out to be positioned randomly in respect to the nuclear matrix. The data are discussed in the framework of the hypothesis postulating that the nuclear matrix plays an important role in determining the positions of recombination-prone areas.Key words: Nuclear matrix, Topoisomerase II, Chromosomal rearrangements, Translocations t(8;21), Nuclear halos, FISH SummaryBreakpoint cluster regions of the AML-1 and ETO genes contain MAR elements and are preferentially associated with the nuclear matrix in proliferating HEL cells

Common chromatin structures at breakpoint cluster regions may lead to chromosomal translocations found in chronic and acute leukemias

“…In this report, we determined that the breakpoint cluster regions of BCR, ABL and AF4 have similar chromatin structures as the breakpoint cluster regions of MLL, AF9, AML-1 and ETO (Aplan et al 1996;Strissel et al 1998bStrissel et al , 2000Strick et al 2000;Bode et al 2000;Hensel et al 2001;Zhang et al 2002;Iarovala et al 2004). All seven genes are involved in chromosomal translocations found in both acute and chronic de novo and therapyrelated leukemia.…”

“…Topo II was first implicated in illegitimate recombination events at the mouse immunoglobulin kappa (Igj) gene intronic SAR associated with an enhancer element (Sperry et al 1989). Many DNase I HS sites are associated with transcriptional regulatory DNA elements and SARs at gene boundaries, but are also found within genes co-localizing with SARs and/or topo II sites at breakpoint cluster regions in IFN, MLL, AF9, AML1 and ETO (Aplan et al 1996;Strissel et al 1996aStrissel et al , b, 1998aStrissel et al , b, 2000Strick et al 2000;Bode et al 2000;Zhang et al 2002, Iarovala et al 2004 (Table 1).…”

Assessment of UCOE on Recombinant EPO Production and Expression Stability in Amplified Chinese Hamster Ovary Cells

“…Earlier studies showed that S/MAR elements may comprise targets of DNA recombination or rearrangement events. Examples may include the many deletions and translocations observed in leukaemia and breast cancer that were related with S/MAR elements [46,47]. In addition, S/MAR elements may be targets for retroviral integration which often occurs within or close to S/MARs [48].…”

An unusual extended DNA loop attachment region is located in the human dystrophin gene

“…Furthermore, we have found that the major recombination hot spot of the dystrophin gene is located within one of these regions. In a separate study we have demonstrated that in other genes the recombinationprone regions (breakpoint cluster regions) are located within the regions of DNA attachment to the nuclear matrix (Svetlova et al, 2001;Iarovaia et al, 2004b). We argue that DNA topoisomerase II of the nuclear matrix can stimulate directly or indirectly (via introduction of double-stranded breaks into DNA) the recombination event within matrix attachment regions or between different matrix attachment regions (Kantidze et al, 2006;Umanskaya et al, 2006).…”

“…This supposition is further supported by colocalization of recombination breakpoints with the sites of DNA cleavage during initial stages of apoptosis (Stanulla et al, 1997a,b), as it is known that this cleavage proceeds via excision of DNA loops and loop oligomers (Lagarkova et al, 1995). Furthermore, detailed analysis of several known recombination hot spots has demonstrated that they are located at the basements of DNA loops (Bode et al, 2000;Svetlova et al, 2001;Iarovaia et al, 2004b).…”