Determination of protein-protein interactions of human eleven-nineteen lysine-rich leukemia protein ELL2

Eleven-nineteen lysine-rich leukemia (ELL) genes produce protein factors that aid in transcription elongation. ELL1 was originally found as a fusion partner with MLL in some multiple lineage leukemias. ELL2 mRNA and protein are induced 6-fold in plasma cells. ELL1 and ELL2 are very similar except for 2 regions between amino acids 352 - 443 and 473 - 516, indicating that they may have different sets of interacting proteins. Yeast two-hybrid (Y2H) assays were performed to determine what proteins might interact with each ELL. ELL2, was subcloned into four main sections (A1, A2, B, and C) to determine specific locations of interaction. The C portion of ELL2, aa 516 to 640, autoactivated transcription in the Y2H and was not further analyzed. Meanwhile, the A1 region interacted with CEP192 (regulator of pericentriolar material recruitment, centrosome maturation, and centriole duplication in mammalian cells); the A2 region interacted with RP3 gene (XLRP gene 3), FIGNLI (new subfamily member of ATPases associated with diverse cellular activities); and the B region interacted with HIFIA (transcription factor found in mammalian cells under reduced oxygen tension that plays an essential role in hypoxia) and SEC63 (a translocation protein). Further mapping of the interactions of the ELLs may help us to clarify their functions in gene regulation and plasma cell development.