Differential regulation of the alpha 2 beta 1 and alpha IIb beta 3 integrin genes during megakaryocytic differentiation of pluripotential K562 cells.

M.M Zutter,A.M Fong,H.R Krigman,S.A Santoro

doi:10.1016/s0021-9258(19)88691-x

M.M Zutter, A.M Fong + Show 2 more

Open Access

https://doi.org/10.1016/s0021-9258(19)88691-x

Copy DOI

Abstract

Expression of the alpha 2 beta 1 and alpha IIb beta 3 integrin genes is differentially regulated during megakaryocytic differentiation of pluripotent K562 cells induced with phorbol 12,13-dibutyrate. Upon megakaryocytic differentiation, steady-state alpha 2 mRNA increased markedly from the undetectable level present in the uninduced cells. The level of beta 1 mRNA did not change. Expression of alpha IIb beta 3 is regulated differently. beta 3 mRNA was undetectable in uninduced cells but increased significantly following induction. alpha IIb mRNA was detectable at a low level prior to induction, but at an increased level following differentiation. Altered mRNA stability did not contribute to changes in mRNA levels. Nuclear run-off experiments revealed a 20-fold increase in alpha 2 gene transcription upon megakaryocytic differentiation, but no change in transcription of the beta 1 gene. Transcription of both the alpha IIb and beta 3 genes increased 10- and 5-fold, respectively. Thus, the increase in alpha 2 beta 1 protein which accompanies the megakaryocytic differentiation of K562 cells is a consequence of the increased steady-state level of alpha 2 mRNA due to transcriptional activation of the alpha 2 gene. The long-lived beta 1 mRNA is not altered during differentiation. In contrast, increased alpha IIb beta 3 protein appears due to increased steady-state levels of both alpha IIb and beta 3 mRNAs that result from transcriptional activation of both integrin genes.

Highlights

Expression of the azBland ffIId 3 integrin genes is K562 cells, a multipotential hematopoietic cell line estabdifferentially regulated during megakaryocytic differ- lished from the pleuraleffusion of a patient with a Philadelentiation of pluripotent K 5 6 2 cells induced with phor- phia chromosome-positive, chronic myelogenous leukemia in bo1 12,13-dibutyrate
Message Stability-To determine the half-lives of a*,PI, allb, and fi:, mRNA prior to induction or following 4 days of induction with phorbol dibutyrate, total cellular RNA was isolated from induced and uninduced K562 cells which were treated with actinomycin D (7.5 pglml), aninhibitor of further gene transcription, for 4,8, 12, and 24 h
Steady-stateLevels of Integrin mRNA AreAltered Following Phorbol Ester Treatment-Megakaryocytic differentiation of the pluripotential hematopoietic cell line K562 with 40 nM phorbol dibutyrate is accompanied by striking increases in cell surface expression of the a& and CYIIbP3 integrins

Summary

Introduction

Expression of the azBland ffIId 3 integrin genes is K562 cells, a multipotential hematopoietic cell line estabdifferentially regulated during megakaryocytic differ- lished from the pleuraleffusion of a patient with a Philadelentiation of pluripotent K 5 6 2 cells induced with phor- phia chromosome-positive, chronic myelogenous leukemia in bo1 12,13-dibutyrate. Message Stability-To determine the half-lives of a*,PI, allb, and fi:, mRNA prior to induction or following 4 days of induction with phorbol dibutyrate, total cellular RNA was isolated from induced and uninduced K562 cells which were treated with actinomycin D (7.5 pglml), aninhibitor of further gene transcription, for 4,8, 12, and 24 h.

Results

Conclusion