Role of Noncoding RNAs Emerging from PU.1 Gene Locus

PU.1 levels are critical for normal hematopoiesis and, even modest alterations can lead to leukemias and lymphomas. To achieve optimal expression of the PU.1 gene at different stages of hematopoiesis, multiple interactions are required between its regulatory elements to form fine chromatin architecture. Preliminary studies have demonstrated a novel mechanism of gene regulation through coordinated expression of the target gene and its regulatory natural noncoding transcripts. While significant advances have been made in understanding which PU.1 locus chromatin states are active or silent, nothing is known how these states are propagated and maintained. In this study I aim to investigate mechanisms of noncoding RNA involvement in formation of alterant chromatin states and shed light on the interplay between well established epigenetic marks (such as nucleosome positioning, histone modification, and DNA methylation) and the emerging class of new epigenetic marks: noncoding RNAs. Therefore I will investigate the functional effect of noncoding RNAs ablation on the formation of the active chromatin configuration and the expression of the PU.1 gene and, ultimately, on hematopoietic stem cell (HSC) fate. Accomplishment of these aims will enable us to understand the roles of noncoding RNAs corresponding to the PU.1 gene locus in the regulation of hematopoietic stem cell differentiation and to identify naturally occurring RNA-mediated regulatory mechanisms, the manipulation of which might lead to critical changes in cell fate and provide knowledge of how changes in noncoding RNAs can lead to disorders of hematopoietic stem cell function and leukemia.