Isolation and Partial Characterization of Proteins Involved in Maternal Transfer of Selenium in the Western Fence Lizard (Sceloporus occidentalis)

Jason M. Unrine¹, Brian P. Jackson², William A. Hopkins³, and Christopher Romanek^1,4

¹Advanced Analytical Center for Environmental Sciences, Savannah River Ecology Laboratory,
University of Georgia, P.O. Drawer E, Aiken, South Carolina 29802, USA
²Departments of Chemistry and Earth Sciences, Dartmouth College,
6105 Fairchild Hall, Hanover, New Hampshire 03765, USA
³Wildlife Ecotoxicology & Physiological Ecology Program, Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, 100 Cheatham Hall, Blacksburg, Virginia 24061, USA
⁴Department of Geology, University of Georgia, Geography–Geology Building, Athens, Georgia 30602, USA

Abstract: Selenium from dietary exposure is efficiently transferred from mother to offspring in oviparous vertebrates, where it can cause severe teratogenic effects. We isolated and partially characterized proteins involved in maternal transfer of selenium in the oviparous lizard Sceloporus occidentalis using size-exclusion chromatography, inductively coupled plasma–mass spectrometry, and polyacrylamide gel electrophoresis. Selenium from dietary selenomethionine exposure was incorporated into at least three egg proteins. One of these proteins was lipovitellin. The other two proteins may be part of a previously unknown mechanism of maternal transfer of Se that is independent of vitellogenesis or albumin secretion. Our results suggest at least three pathways for maternal transfer of Se in vertebrates that may vary in importance depending on the species.

Keywords: Maternal transfer, Selenium, Sceloporus occidentali, Inductively coupled, plasma–mass spectrometry, Size-exclusion chromatography