ONCOGENES IN MURINE ACUTE MYELOID LEUKEMIA

c-myb和Mml 1、2和3继续是实验室的焦点，因为我们已经发现这些位点对前单核细胞白血病的发展是重要的。这些是逆转录病毒在我们的动物模型中插入突变的靶点。此外，今年我们还发现了新的前病毒插入位点，称为Mml 4和5。我们的实验室已经表明，当逆转录病毒整合到该位点时，编码转录因子的c-myb癌基因可以在前单核细胞白血病中被激活。在此之前，我们的特点是这种基因可以通过逆转录病毒插入和这种整合的机械后果激活的许多方式。最近，一个主要的目标一直是描述这种转录因子在白血病细胞中的功能作用。特别是，我们感兴趣的是鉴定由该转录因子调控的参与增殖和抗凋亡过程的靶基因。今年，我们继续研究，表明c-myc是一个重要的靶点，c-Myb蛋白通过它对增殖发挥积极作用。使用Myb-雌激素受体融合蛋白和显性负性Myb-雌激素受体蛋白，这两者都可以被他莫昔芬迅速诱导，我们已经证明，c-Myb调节c-myc在转录水平。这些数据证实了使用条件诱导c-myb基因转录通过载体与金属硫蛋白启动子。我们正在以两种方式扩大对目标的研究。首先，我们正在寻找新的靶基因的c-Myb使用微阵列技术和第二，我们正在寻找基因的调控相关基因B-Myb。候选目标已经确定。我们发现，Mml 1，Mml 2和Mml 3基因座分别与急性单核细胞白血病的一个子集的发展和所有三个映射到染色体10上的同一区域。虽然它们在同一BAC克隆上连接，但它们彼此分开大于20 kb。目前，该实验室的一个主要重点是表征这些基因座的转录本，这些基因座可能编码一个新的原癌基因或肿瘤抑制基因。已对大于60 kb的该区域进行了测序，从而发现了几个同源EST，这些EST可用于鉴定由该区域编码的基因。我们目前正在确定这些基因中是否有任何一个由于前病毒在一般区域的整合而在转录中发生了改变。此外，我们通过使用逆转录病毒插入诱变，确定了另外两个明显新的位点Mml 4和Mml 5，它们位于染色体10以外的染色体上。其中一个被定位在13号染色体上。- 动物模型，c-myb，插入突变，白血病，蛋白水解，逆转录病毒，-非人类受试者或人类组织

c-myb and Mml 1,2 and 3 continue to be the focus of the laboratory since we have found that these loci are important to the development of promonocytic leukemia. These are targets of insertional mutagenesis by retroviruses in our animal model. In addition, this year we have found new proviral insertion sites called Mml4 and 5.Our laboratory has shown that the c-myb oncogene, which encodes a transcription factor, can be activated in promonocytic leukemias when the retrovirus integrates into the locus. Previously, we characterized the many ways this gene can be activated by retroviral insertion and the mechanistic consequences of this integration. Recently, a major goal has been to characterize the functional role of this transcription factor in leukemic cells. In particular, we are interested in identifying target genes regulated by this transcription factor that are involved in proliferation and anti- apoptotic processess. This year we have continued studies which have show that c-myc is an important target through which the c-Myb protein exerts its positive effect on proliferation. Using both a Myb-estrogen receptor fusion protein and a dominant negative Myb-estrogen receptor protein, both of which can be induced rapidly by tamoxifen, we have demonstrated that c-Myb regulates c-myc at the transcriptional level. These data were confirmed using conditional induction of c-myb gene transcription via a vector with a metallothionein promoter. Our studies on targets are being extended in two ways. First, we are looking for new target genes of c-Myb using microarray technology and second, we are looking for genes that are regulated by a related gene B-Myb. Candidate targets have already been identified. We discovered that the loci Mml1,Mml2 and Mml3 are individually associated with the development of a subset of acute monocytic leukemias and all three map to the same region on chromosome 10. Although they are connected on the same BAC clone they are separated from each other by greater than 20 kb. Presently, a major focus of the laboratory is the characterization of transcripts from these loci that may encode a new proto-oncogene or tumor suppressor gene. Greater than 60 kb of this region have been sequenced resulting in the finding of several homologous ESTs which have been useful in the identification of genes encoded by this region. We are presently determining if any of these genes is altered in its transcription due to integration of proviruses in general region. In addition, we identifed through the use of retroviral insertional mutagenesis, two other apparently novel loci Mml4 and Mml5 that are located on chromosomes other than chromosome 10. On of this has been mapped to chromosome 13. - animal model, c-myb, Insertional Mutagenesis, Leukemia, proteolysis, retrovirus, - Neither Human Subjects nor Human Tissues