title: Dynein Light Chain 1 (DYNLT1) Interacts with Normal and Oncogenic Nucleoporins.
abstract: The chimeric oncoprotein NUP98-HOXA9 results from the t(7;11)(p15;p15) chromosomal translocation and is associated with acute myeloid leukemia. It causes aberrant gene regulation and leukemic transformation through mechanisms that are not fully understood. NUP98-HOXA9 consists of an N-terminal portion of the nucleoporin NUP98 that contains many FG repeats fused to the DNA-binding homeodomain of HOXA9. We used a Cytotrap yeast two-hybrid assay to identify proteins that interact with NUP98-HOXA9. We identified Dynein Light Chain 1 (DYNLT1), an integral 14 KDa protein subunit of the large microtubule-based cytoplasmic dynein complex, as an interaction partner of NUP98-HOXA9. Binding was confirmed by in vitro pull down and co-immunoprecipitation assays and the FG repeat region of NUP98-HOXA9 was shown to be essential for the interaction. RNAi-mediated knockdown of DYNLT1 resulted in reduction of the ability of NUP98-HOXA9 to activate transcription and also inhibited the ability of NUP98-HOXA9 to induce proliferation of primary human hematopoietic CD34+ cells. DYNLT1 also showed a strong interaction with wild-type NUP98 and other nucleoporins containing FG repeats. Immunofluorescence analysis showed that DYNLT1 localizes primarily to the nuclear periphery, where it co-localizes with the nuclear pore complex, and to the cytoplasm. Deletion studies showed that the interactions of the nucleoporins with DYNLT1 are dependent predominantly on the C-terminal half of the DYNLT1. These data show for the first time that DYNLT1 interacts with nucleoporins and plays a role in the dysregulation of gene expression and induction of hematopoietic cell proliferation by the leukemogenic nucleoporin fusion, NUP98-HOXA9.
authors.affiliation: Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, Missouri, United States of America.
authors.forename: Nayan J
authors.initials: NJ
authors.lastname: Sarma
authors.forename: Nabeel R
authors.initials: NR
authors.lastname: Yaseen
mesh_terms: D004398:Dyneins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D018398:Homeodomain Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D020014:K562 Cells; D022022:Nuclear Pore / Q000378:metabolism; D028861:Nuclear Pore Complex Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport; D020449:Repetitive Sequences, Amino Acid; D015533:Transcriptional Activation
chemical_list: C533376:DYNLT1 protein, human; D018398:Homeodomain Proteins; D028861:Nuclear Pore Complex Proteins; C097899:homeobox protein HOXA9; C093350:nuclear pore complex protein 98; D004398:Dyneins