Year: 2004
Type: article
Abstract: Ets transcription factors have been implicated in the development, regulation, and survival of numerous hematopoietic derived cells, including B and T-lymphocytes.E26 avian leukemia oncogene-2 (Ets-2) is an Ets family member transcription factor.Strong expression of Ets-2 is observed in developing thymocytes from the DN1 stage and in Bcells from the pro-B stage.A conserved sequence within the Ets-2 pointed domain amino acids 69 to 73 PLLTP is able to interact with the Map kinase ERK.Threonine seventytwo is phosphorylated by ERK1, and permits transactivation by Ets-2.Mutation of this residue from a threonine to an alanine, Ets-2 T72A, abrogates Ras mediated transactivation of Ets-2.Based on this evidence, we hypothesized that Ets-2 was important in T-and B-cell development, activation, and function.To test this hypothesis we analyzed Ets-2 activation in T-cell lines, and created two transgenic mice lines that express Ets-2 T72A in either developing T-cells or B-cells.Transactivation of Ets-2 can be induced by both Ras activation and by phorbol 12-myristate 13-acetate and ionomycin stimulation in the Jurkat T-cell line.In-vitro analysis of Ets-2 activation by ionomycin results in a rapid, but transient Ets-2 band shift as evidenced by western blot analysis of protein extracts from thymocytes.Transgenic mice that over-express Ets-2 T72A in the thymus displayed a dramatic reduction in thymus size associated with hypocellularity.iii This reduction was associated with a partial developmental block at the double negative 2 and double negative 3 stage of development, a twenty-fold increase in c-Kit + expression, and a five-fold increase the CD5 low population.Further, thymocytes from the transgenic mice have increased apoptosis both in-vitro and in-vivo compared to non-transgenic littermates.Transgenic mice that over-express Ets-2 T72A in B-lymphocytes revealed a loss of the B220 Hi population of B-cells in the bone marrow.This population consists of mature B-cells that are characterized to be IgM + , IgD + and Cd49d + mature lymphocytes.Analysis of transgenic Ets-2 T72A B-cells in other secondary lymph organs did not reveal any defects.This dissertation demonstrates that Ets-2 is an important target in lymphocyte development and function.It is involved in T-cell development and survival and in establishment of mature bone marrow B-cells.x Luciferase assay . . . . . . . . . . . . . . . . . . . . . .
Author: Ian Fisher
Institution: The Ohio State University
Language: English
Topic: T-cell and B-cell Immunology
Subfield: Immunology
Field: Immunology and Microbiology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2396802762