It has been argued that most Y chromosome coded genes are likely to have roles in sperm production or function. However, it is not clear if these genes provide essential spermatogenic function or just potentiate the spermatogenic process. The goal of this application is to determine the minimum Y chromosome gene requirement that is compatible with successful reproduction by assisted reproductive technologies (ART). The hypothesis of this application is that a Y gene complement of as few as two or three genes is enough to enable the production of male `gametes'(round spermatids or sperm) that are capable of participating in fertilization if delivered into the oocytes via injection. In preliminary data we provide evidence that in the mouse the presence of only two Y-coded genes, Sry and Eif2s3y, allows formation of testes, ongoing spermatogonial proliferation, and completion of meiosis to generate round spermatids. We suggest that further addition of one copy of Zfy is sufficient to allow the production of some sperm, albeit with morphologically abnormal heads. We also show that assisted reproduction by ICSI and IVF enable the generation of live offspring from subfertile and infertile males with Y chromosome deficiencies. In this application we will focus on analyzing various mouse models with limited Y gene complements: (1) males with an almost intact Y short arm but complete absence of Y long arm genes;(2) males with no Y long arm genes and the known Y short arm genes limited to Sry, Eif2s3y, a single copy of Zfy, and a reduced number of copies of Rbmy;and (3) males with only Eif2s3y and Sry.
In Specific Aim 1 we will generate these males with limited Y gene complements and define more precisely at what stage of spermiogenesis cells arrest or become abnormal. We will perform histological analysis of the testes, confirm the presence of specific spermatogenic cell types by immunostaining, and examine acrosome development as a marker of spermiogenic stage.
In Specific Aim 2 we will use sperm and/or round spermatids from these models for ICSI and/or ROSI. We will observe early post-fertilization events after injection, obtain embryos, and produce live offspring. We will genotype progeny to test which sperm genotypes were successful in supporting fertilization and embryo development. The significance of this application is that it will advance the understanding of the role of Y chromosome encoded genes in spermatogenesis and sperm function;it will also provide valuable information for those using ART to treat human infertility associated with Y gene deficiencies.

Public Health Relevance

In this application we seek to determine the minimum Y gene complement that is compatible with the generation of sperm competent in fertilization via ART (ICSI and ROSI). The study will add to the understanding of the functions of Y chromosome coded genes by defining which Y genes provide essential spermatogenic function rather than just potentiating the spermatogenic process. The application also has significance for those utilizing ART to treat male infertility.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21HD058059-02
Application #
7582426
Study Section
Cellular, Molecular and Integrative Reproduction Study Section (CMIR)
Program Officer
Moss, Stuart B
Project Start
2008-04-01
Project End
2012-03-31
Budget Start
2009-04-01
Budget End
2012-03-31
Support Year
2
Fiscal Year
2009
Total Cost
$173,000
Indirect Cost
Name
University of Hawaii
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
965088057
City
Honolulu
State
HI
Country
United States
Zip Code
96822
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Riel, Jonathan M; Yamauchi, Yasuhiro; Sugawara, Atsushi et al. (2013) Deficiency of the multi-copy mouse Y gene Sly causes sperm DNA damage and abnormal chromatin packaging. J Cell Sci 126:803-13
Sugawara, Atsushi; Sato, Brittany; Bal, Elise et al. (2012) Blastomere removal from cleavage-stage mouse embryos alters steroid metabolism during pregnancy. Biol Reprod 87:4, 1-9
Raunig, J M; Yamauchi, Y; Ward, M A et al. (2011) Placental inflammation and oxidative stress in the mouse model of assisted reproduction. Placenta 32:852-8
Raunig, Jefferey M; Yamauchi, Yasuhiro; Ward, Monika A et al. (2011) Assisted reproduction technologies alter steroid delivery to the mouse fetus during pregnancy. J Steroid Biochem Mol Biol 126:26-34
Riel, Jonathan M; Yamauchi, Yasuhiro; Huang, Thomas T F et al. (2011) Short-term storage of human spermatozoa in electrolyte-free medium without freezing maintains sperm chromatin integrity better than cryopreservation. Biol Reprod 85:536-47
Cocquet, Julie; Ellis, Peter J I; Yamauchi, Yasuhiro et al. (2010) Deficiency in the multicopy Sycp3-like X-linked genes Slx and Slxl1 causes major defects in spermatid differentiation. Mol Biol Cell 21:3497-505
Yamauchi, Yasuhiro; Riel, Jonathan M; Stoytcheva, Zoia et al. (2010) Deficiency in mouse Y chromosome long arm gene complement is associated with sperm DNA damage. Genome Biol 11:R66
Cocquet, Julie; Ellis, Peter J I; Yamauchi, Yasuhiro et al. (2009) The multicopy gene Sly represses the sex chromosomes in the male mouse germline after meiosis. PLoS Biol 7:e1000244
Yamauchi, Yasuhiro; Riel, Jonathan M; Wong, Samantha J et al. (2009) Live offspring from mice lacking the Y chromosome long arm gene complement. Biol Reprod 81:353-61