Vitellogenesis, the process whereby yolk lipoproteins are synthesized by the liver and accumulated in the developing oocyte, is of fundamental importance for the successful reproduction of non-mammalian vertebrates. This process is considered an excellent model system for the hormonal regulation of sex-differentiated hepatic protein synthesis in vertebrates. Accordingly, the main objective of this proposal is to understand the hormonal interplay for the expression of female specific hepatic genes under the chronic stress of captivity in the lizard Anolis pulchellus. Of major relevance is that cardiovascular disease and reproductive malfunctioning in humans have been related to altered sex-linked hepatic protein metabolism. In addition, it has also been shown that exposure to stress triggers the onset of these malfunctions. Therefore, studies of the regulation of vitellogenin gene expression could provide important insights in the genesis and treatment of these hepatic diseases for which no experimental models are available in humans. In previous studies we have shown that anoline lizards undergo pronounced reproductive regression under captivity stress, including a drastic decrease of the synthesis of vitellogenin by the liver paralleled to a decrease in VTG mRNA levels, cessation of follicular growth and ovulation, increased follicular atresia, and degeneration of the oviductal glands. Estrogen therapy to captive female lizards greatly improves reproductive activity and prevents or reverts the negative effect of captivity on vitellogenin synthesis and secretion by the liver. Since stress responses have been related to the alteration of hormone levels of the pituitary-adrenal axis, we suggest that the detrimental effects of captivity evoked in female specific liver functions are mediated through altered levels of glucocorticoids which, in turn, result in the faulty expression of estrogen dependent genes. Three main mechanisms are considered in our research plan: 1) reduction of estrogen levels, 2) reduction of the hepatic estrogen receptor (HER) levels/activity, and/or 3) estrogen competitive interactions at the gene regulatory site. Therefore, we propose: 1) To analyze the mechanisms of VTG gene expression during captivity at the molecular level by determining VTG protein synthesis, mRNA levels and transcriptional rates and evaluate the effect of estrogen and the activity/levels of the hepatic estrogen receptor. 2) To characterize the multihormonal interplay involved in VTG gene expression under stress and different hormonal treatments in vivo and in vitro. 3) To initiate structural studies of the Anolis VTG genes including the isolation of the 5' regulatory regions using homologous cDNA probes recently cloned in our laboratory. This will lead to future analysis of the interaction of hormone-receptor complexes at the regulatory sites. This research proposal will provide a rich environment for student training in biomedical research.

Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Puerto Rico Rio Piedras
San Juan
United States
Zip Code
Ramírez-Camejo, Luis A; Maldonado-Morales, Génesis; Bayman, Paul (2017) Differential Microbial Diversity in Drosophila melanogaster: Are Fruit Flies Potential Vectors of Opportunistic Pathogens? Int J Microbiol 2017:8526385
Morales-Rivera, Keyla F; Piñero Cruz, Dalice M; Prieto, Jose A (2017) Crystal structure of (-)-(S)-4-[(2S,3S,4S,Z)-3-hydroxy-4-methyl-hept-5-en-2-yl]-1,3-dioxolan-2-one. Acta Crystallogr E Crystallogr Commun 73:1070-1072
García-Arriaga, Marilyn; Acosta-Santiago, Maxier; Cruz, Antony et al. (2017) Probing the Limits of Supramolecular G-Quadruplexes Using Atomistic Molecular Dynamics Simulations. Inorganica Chim Acta 468:209-222
Huang, Qing; Quiñones, Edwin (2016) A spectroscopic method to determine the activity of the restriction endonuclease EcoRV that involves a single reaction. Anal Biochem 497:103-5
Mège, Pascal; Schizas, Nikolaos V; Reyes, Joselyd García et al. (2015) Genetic seascape of the threatened Caribbean elkhorn coral, Acropora palmata, on the Puerto Rico Shelf. Mar Ecol (Berl) 36:195-209
Morales-Rivera, Amarilys; Hernández-Burgos, Mayté M; Martínez-Rivera, Arlene et al. (2014) Anxiolytic effects of oxytocin in cue-induced cocaine seeking behavior in rats. Psychopharmacology (Berl) 231:4145-55
Ramírez-Camejo, Luis A; Torres-Ocampo, Ana P; Agosto-Rivera, José L et al. (2014) An opportunistic human pathogen on the fly: strains of Aspergillus flavus vary in virulence in Drosophila melanogaster. Med Mycol 52:211-9
Martínez-Rivera, Arlene; Rodríguez-Borrero, Enrique; Matías-Alemán, María et al. (2013) Metabotropic glutamate receptor 5 within nucleus accumbens shell modulates environment-elicited cocaine conditioning expression. Pharmacol Biochem Behav 110:154-60
Galindo-Cardona, Alberto; Acevedo-Gonzalez, Jenny P; Rivera-Marchand, Bert et al. (2013) Genetic structure of the gentle Africanized honey bee population (gAHB) in Puerto Rico. BMC Genet 14:65
Santiago-Rodriguez, Tasha M; Rivera, Jessica I; Coradin, Mariel et al. (2013) Antibiotic-resistance and virulence genes in Enterococcus isolated from tropical recreational waters. J Water Health 11:387-96

Showing the most recent 10 out of 194 publications