(IMAGE) Kumamoto University Caption Deletion of hsf5 in mice results in the impaired development of testis (left), and the absence of spermatids and spermatozoa (right), which leads to the failure of sperm formation. Credit Kei-ichiro Ishiguro, Kumamoto University Usage Restrictions Cannot be used without prior permission License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.