Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

References

Discussion
Board

The sarco(endo)plasmic reticulum Ca2+ -ATPase is encoded by three genes SERCA 1-3. Two 3' spliced variants of SERCA 1 and 2 genes have been prev iously described in many species. We also identified two different SERCA 3 mRNA populations by RNase protection analysis. We then isolated and sequenced the 3'end portion of the mouse SERCA 3 gene, and confirmed the presence of an alternative mRNA transcript by sequencing a cDNA fragment obtained by RT-PCR.Tissue distribution of the spliced variants was studied in mouse by RT-PCR: SERCA 3b was the only isoform expressed in endothelial cells from aorta and heart and was also the major isoform in lung and kidney, whereas SERCA 3a and b were coexpressed in trachea, intestine, thymus, spleen and fetal liver. SERCA 2a and 2b are both present in aortic smooth muscle cells (ASMC). We studied expression of the SERCA isoforms by immunofluorescence and RT-PCR and the functional Ca2+ pools on Fura-2 loaded cells. We demonstrated that proliferation of ASMC in culture is associated with loss of SERCA 2a and of the caffeine-sensitive store. When cells stopped proliferating at confluency they reacquired both sensitivity to caffeine and expression of SERCA 2a. Thus proliferation of ASMC is associated with reorganization of the Ca2+ pools.

Back to the top.
Presentation Number SAlompré 0338
Keywords: SERCA, gene expression, smooth muscle, splicing