Research Program                    

My Laboratory is focusing on two research areas: 1) Functions and molecular mechanisms of the peptide hormones in embryogenesis, and 2) nongenomic actions of steroids.

Establish a model for studying functions of prolactin superfamily in early development

The growth hormone and prolactin superfamily, which includes the mammalian placental lactogen and somatolactin in teleost, are important in hundreds of different physiological processes. However, we know very little about the roles of growth hormone and prolactin during early embryonic development. Recently, we have demonstrated that prolactin is an important regulator for the normal development of the eyes, brain, melanophores and body size in zebrafish. For the first time, prolactin was demonstrated to be functional and important for the development of several organs/tissues during embryogenesis in a vertebrate species. Understanding prolactin-regulated developmental processes and signaling molecules will facilitate the development of therapeutic protocols and reagents that can be used to control proper development and attenuate disease associated with abnormal development of organs/tissues. Our long-term goal is to establish physiological functions and signaling mechanisms of the prolactin superfamily during early development and contribute to the development of applications in aquaculture and agriculture, and treatments in human diseases.

Establish a model for studying non-genomic actions of progestin

The effects of steroids in vertebrates have been well defined as genomic and nongenomic in order to differentiate non-transcriptional steroid activities (non-genomic) from the nuclear steroid receptor mediated transcriptional regulatory activity. Evidence strongly suggests that nongenomic actions of steroids are regulated by receptors localized on or near the plasma membrane. However, the identity of the receptor responsible for the rapid or non-genomic actions of the steroids is still under debate. I was the first to clone and characterize a novel family of membrane progestin receptor (mPR) in vertebrates. The newly discovered mPRs are unrelated to nuclear steroid receptors or any other steroid binding proteins characterized to date. Additional evidence from my laboratory and other laboratories further

demonstrates that the mPRs are the functional membrane progestin receptors with the ability to mediate nongenomic actions of the progestins. The long-term goal of my research is to establish zebafish oocytes and their surrounding follicle cells as a model for the studying of the functions and signaling pathways of the mPRs in vertebrates.

Courses Taught

BIOL 3320 Principles of Animal Physiology

BIOL 5630 Comparative Animal Physiology

BIOL 6082 Vertebrate Endocrinology

BIOL 7630 Fish Physiology  

Recent Publications

1.     Nguyen, N, Zhu Y (in press) Prolactin functions as a survival factor during zebrafish embryogenesis. Comp Biochem Physiol A Mol Integr Physiol.

2.     Hanna R, Zhu Y (in press) Expression of membrane progestin receptors in zebrafish (Danio rerio) oocytes, testis and pituitary. General and Comparative Endocrinology

3.     Nguyen N, Stellwag EJ, Zhu Y (2008) Prolactin modulating organogenesis in the vertebrate-recent discoveries in zebrafish. Comp Biochem Physiol C Toxicol Pharmacol. 148:370-380.

4.     ZhuY, HannaRN, SchaafMJM, Spaink HP, ThomasP (2008) Candidates for membrane progestin receptors in vertebrate gametes—past approaches and future challenges. Comp Biochem Physiol C Toxicol Pharmacol. 148:381-389.

5.     Summers K, Zhu Y (2008) Positive selection on a prolactin paralog following gene duplication in cichlids: adaptive evolution in the context of parental care? Copeia, 4: 872-976.

6.     Xie C, Nguyen N, Zhu Y, Li Q (2007) Detection of the recombinant proteins in single transgenic microbial cells using laser tweezers and ramen spectroscopy. Analytical Chemistry 79:9269-9275.

7.     Zhu Y, Song D, Tran N, Nguyen N (2007)The effects of the members of growth hormone family knockdown in zebrafish development. General and Comparative Endocrinology 150: 395-404.

8.     Thomas P, Pang Y, Dong J, Groenen P, Kelder J, de Vlieg J, Zhu Y, Tubbs C (2007) Steroid and G Protein Binding Characteristics of the Seatrout and Human Progestin Membrane Receptor Alpha Subtypes and Their Evolutionary Origins. Endocrinology 148: 705-718.

9.     Hanna RN, PangY, ThomasP, Zhu Y (2006) Cell Surface Expression, Progestin Binding and Rapid Nongenomic Signaling of Zebrafish Membrane Progestin Receptors α and β in Transfected Cells. Journal of Endocrinology 190: 247 - 260.

10.  Nguyen N, Sugimoto M, Zhu Y (2006) Production and purification of recombinant somatolactin β and its effects on melanosome aggregation in zebrafish. General and Comparative Endocrinology 145: 182-187.

11.  Zhu Y, Stiller JW, Shaner MP, Baldini A, Scemama JL, Capehart AA (2004) Cloning of somatolactin a and b cDNAs in zebrafish and phylogenetic analysis of two distinct somatolactin subtypes in fish. Journal of Endocrinology 182: 509-518.

12.  Thomas P, Pang Y, Zhu Y, Detweiler C, Doughty K (2004) Multiple rapid progestin actions and progestin membrane receptor subtypes in fish. Steroids 69:567-573.

13.  Zhu Y, Rice CD, Pang Y, Pace M, Thomas P (2003) Cloning, expression and characterization of a novel membrane progestin receptor and evidence it is an intermediary in meiotic maturation of fish oocytes. Proc. Natl. Acad. Sci. USA 100: 2231-2236.

14.  Zhu Y, Bond JE, Thomas P (2003) Identification, classification and partial characterization of genes in humans and other vertebrates homologous to a novel fish membrane progestin receptor. Proc. Natl. Acad. Sci. USA 100:2237-2242.

Laboratory Personnel

Current Students

Nhu Nguyen, PhD student

Richard Hanna, PhD student

Sean Daly, MS student

Melina Pereira, MS students

Past Students

Michael Shaner, MS

Danyin Song, MS