TSGA10 prevents nuclear localization of the hypoxia‐inducible factor (HIF)‐1α

Abstract

The hypoxia‐inducible factor (HIF)‐1 is a transcriptional regulator of genes involved in oxygen homeostasis. We previously described testis‐specific isoforms of HIF‐1α (mHIF‐1αI.1 and hHIF‐1αTe). Using mHIF‐1α exon I.1 knock‐out mice we confirmed the specific expression of mHIF‐1αI.1 in the sperm tail. A protein–protein interaction between HIF‐1α and the testis specific gene antigen 10 (TSGA10) was identified by yeast two‐hybrid screening. TSGA10 is expressed in testis but also in other organs and malignant tissues. Immunofluorescence analysis indicated that the C‐terminal part of TSGA10 accumulates in the midpiece of spermatozoa, where it co‐localizes with HIF‐1α. HIF‐1α nuclear localization and HIF‐1 transcriptional activity were significantly affected by overexpressed TSGA10.