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Oxidative Medicine and Cellular Longevity
Volume 2017 (2017), Article ID 7295319, 11 pages
https://doi.org/10.1155/2017/7295319
Research Article

REGγ Contributes to Regulation of Hemoglobin and Hemoglobin δ Subunit

1Shanghai Key Laboratory of Regulatory Biology, Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
2Department of Infectious Diseases, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
3Key Laboratory of Epigenetics and Oncology, the Research Center for Preclinical Medicine, Southwest Medical University, Sichuan 646000, China
4Department of Molecular and Cellular Biology, Dan L. Duncan Cancer Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA

Correspondence should be addressed to Junjiang Fu, Jiwu Chen, and Xiaotao Li

Received 7 December 2016; Revised 22 April 2017; Accepted 8 May 2017; Published 16 July 2017

Academic Editor: Luciano Saso

Copyright © 2017 Qiuhong Zuo et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Hemoglobin (Hb) is a family of proteins in red blood cells responsible for oxygen transport and vulnerable for oxidative damage. Hemoglobin δ subunit (HBD), a member of Hb family, is normally expressed by cells of erythroid lineage. Expression of Hb genes has been previously reported in nonerythroid and hematopoietic stem cells. Here, we report that Hb and HBD can be degraded via REGγ proteasome in hemopoietic tissues and nonerythroid cells. For this purpose, bone marrow, liver, and spleen hemopoietic tissues from REGγ+/+ and REGγ−/− mice and stable REGγ knockdown cells were evaluated for the degradation of Hb and HBD via REGγ. Western blot and immunohistochemical analyses exhibited downregulation of Hb in REGγ wild-type mouse tissues. This was validated by dynamic analysis following blockade of de novo synthesis of proteins with CHX. Degradation of HBD only occurred in REGγ WT cells but not in REGγN151Y, a dominant-negative REGγ mutant cell. Notably, downregulation of HBD was found in HeLa shN cells with stimulation of phenylhydrazine, an oxidation inducer, suggesting that the REGγ proteasome may target oxidatively damaged Hbs. In conclusion, our findings provide important implications for the degradation of Hb and HBD in hemopoietic tissues and nonerythroid cells via the REGγ proteasome.