Animal Reproductive Biology Group

Gaurishanker Manandhar

Research Assistant Professor

Phone: 573-882-3329
E-mail: ManandharG@missouri.edu
Address: S141 Animal Science Research Center

Education

M.S., Tribhuvan University, Nepal
Ph.D., Moscow State University-Russia
Postdoc, University of Missouri

Research Focus

Gametes pre-implantation embryo

Research Description

Manandhar is interested in the Ubiquitin-Proteasomal dependent pathway of mammalian sperm-zona penetration.

He is investigating various proteasomal subunits present in the sperm acrosome, various enzymes, regulators that modulate the sperm proteasomal activity during in vivo and in vitro fertilizations.

He is also looking into the ubiquitinated epitopes of the mammalian oocyte zona pellucida that are targeted by the sperm proteasomes.

Manandhar's main research focuses on the various extra-nuclear organelles of the mammalian sperm head and their role in fertilization.

Specifically, he has shown that mammalian spermatozoa degenerate centrosomes partially or completely during spermiogenesis. Manandhar is investigating centrosomes regeneration during the early embryonic development.

In addition, Manandhar is investigating the molecular nature of equatorin. Previous studies have revealed that the resident protein of the equatorial region, equatorin (epitope of the antibody MN9) is expressed only after acrosome reaction when the spermatozoa are ready to fuse with the oocytes.

Manandhar is also studying the post-acrosomal perinuclear theca of sperm heads. As shown in his earlier work and works of other investigators, the diffusible proteins of this region are involved in initiating embryonic cell cycle. Follow-up works are being aimed at identifying the active molecular species of the post-acrosomal perinuclear theca.

Recent Publications

Fischer KA, Van Leyen K, Lovercamp KW, Manandhar G, Sutovsky M, Feng D, Safranski T, Sutovsky P.
15-Lipoxygenase is a component of the mammalian sperm cytoplasmic droplet. Reproduction. 2005 Aug;130(2):213-22. PMID: 16049159
Sutovsky P, Manandhar G, Laurincik J, Letko J, Caamano JN, Day BN, Lai L, Prather RS, Sharpe-Timms KL, Zimmer R, Sutovsky M.
Expression and proteasomal degradation of the major vault protein (MVP) in mammalian oocytes and zygotes. Reproduction. 2005 Mar;129(3):269-82. PMID: 15749954
Manandhar G, Schatten H, Sutovsky P.
Centrosome reduction during gametogenesis and its significance. Biol Reprod. 2005 Jan;72(1):2-13. Epub 2004 Sep 22. Review. PMID: 15385423
Sutovsky P, Manandhar G, McCauley TC, Caamano JN, Sutovsky M, Thompson WE, Day BN.
Proteasomal interference prevents zona pellucida penetration and fertilization in mammals. Biol Reprod. 2004 Nov;71(5):1625-37. Epub 2004 Jul 14. PMID: 15253927
Sutovsky P, Manandhar G, Wu A, Oko R.
Interactions of sperm perinuclear theca with the oocyte: implications for oocyte activation, anti-polyspermy defense, and assisted reproduction. Microsc Res Tech. 2003 Jul 1;61(4):362-78. Review. PMID: 12811742
Manandhar G, Toshimori K.
Fate of postacrosomal perinuclear theca recognized by monoclonal antibody MN13 after sperm head microinjection and its role in oocyte activation in mice. Biol Reprod. 2003 Feb;68(2):655-63. PMID: 12533432
A complete list of publications for G Manandhar in PubMed