Reproduction Abstracts

Introduction: Dysplasia of the fibrous sheath (DFS) and stump-tail sperm is a rare sperm abnormality often associated with parental consanguinity and found to be associated with recessive mode. However, the molecular pathogenesis remain elusive.

Material and methods: Whole-exome sequencing was performed in a typical pedygree with two affected brother. Multiple-tissue real time PCR was used to check the expression of QRICH2 in human multiple tissues. Sperm immunostaining was used to determine the localization of QRICH2 protein in human sperm. Zebrafish whole-mount in situ hybridization was used to check the expression of qrich2 gene during embryo development. Qrich2 Morphonilo was used to silencing qrich2 gene and immunostaining of acetylated tubulin was used to determine whether knock down qrich2 could affect cilia development.

Results and discussion: One testis specific expressed gene, QRICH2, was confirmed that mutated in two brothers with similar phenotypes. AA64 was identified to have a non-sense homozygous mutation of TGA. Multiple-tissue real time PCR showed that it specifically expressed in the tesits. Immunostaining of sperm confirmed that the gene is expressed in the mitochondrial of the sperm. Bioinformatic analysis showed that it interacts with PANK2, which can be confirmed in Co-IP experiment. Knockdown of zebrafish qrich2 gene affect cilia development in KV knob and pronepraph. It is concluded that qrich2 is essential for cilia development possibly through regulation of PANK2 mediated energy metabolism in the mitochondrial of sperm flagella. Supported by National Basic Research Program of China (2012CB944903).