Activation of the megakaryocyte/platelet-specific gene platelet basic protein (PBP) by the ETS family factor PU.1 / Chunyan Zhang.

Format:

Book

Manuscript

Microformat

Thesis/Dissertation

Author/Creator:

Zhang, Chunyan.

Contributor:

Poncz, Mortimer, advisor.

University of Pennsylvania.

Language:

English

Subjects (All):

Penn dissertations--Pathology.

Pathology--Penn dissertations.

Local Subjects:

Penn dissertations--Pathology.

Pathology--Penn dissertations.

Physical Description:

ix, 126 pages : illustrations ; 29 cm

Production:

1997.

Summary:

Platelet Basic Protein (PBP) is a chemokine and is only expressed in megakaryocytes and platelets. In human, this gene is also duplicated. The mechanism underlying the PBP gene's tissue-specific expression is unknown. In this thesis, we used transient expression system and mobility shift analysis to study regulation of the functional human PBP gene. We found that the proximal 0.1 kb region was sufficient to drive reporter gene expression only in megakaryocytic cells and a pyrimidine-rich region between $-$92 and $-$50 bp upstream of the transcriptional start site was shown to contain enhancer element(s). Further mobility shift gel studies with HEL nuclear extracts, recombinant PU.1, and polyclonal anti-PU.1 antibody demonstrated that the Ets family factor PU.1 bound to its cognate site in this region. Point mutations that abrogated PU.1 binding significantly decreased PBP promoter activity in megakaryocytic cells and exogenous expression of PU.1 in HeLa cells could activate PBP promoter activity. However, mutation of the PU.1 binding site decreased this transactivation. In addition, we also examined PBP gene transcription in megakaryocytes differentiated from both wild-type and PU.1 null embryonic stem (ES) cells. We found that PBP gene expression dropped more than four times in the absence of PU.1 compared to expression levels in the presence of PU.1. Therefore, from both cell lines and ES cell studies, we conclude that PU.1 is indispensable for the expression of PBP gene. These studies extend the biological role of PU.1 in the regulation of hematopoietic genes.

Notes:

Supervisor: Mortimer Poncz.

Thesis (Ph.D. in Pathology) -- University of Pennsylvania, 1997.

Includes bibliographical references.

Local Notes:

University Microfilms order no.: 98-00947.

OCLC:

244970944