Activation of multidrug efflux transporter activity at fertilization in sea urchin embryos (Strongylocentrotus purpuratus)

TY - JOUR

T1 - Activation of multidrug efflux transporter activity at fertilization in sea urchin embryos (Strongylocentrotus purpuratus)

AU - Hamdoun, Amro M.

AU - Cherr, Gary N.

AU - Roepke, Troy A.

AU - Epel, David

N1 - Funding Information: We thank Drs. Kathy Foltz and Forest O'Neil for their generous assistance with screening of cDNA macroarray libraries. Drs. Julie Alipaz and Stephen Palumbi are thanked for providing expert guidance with sequencing of the transporter genes and assembly of the sequences. Ms. Nature McGinn is thanked for her assistance with embryo imaging. Dr. Christian Leutenegger provided technical support for q-pcr. This work was funded in part by: UC Coastal Toxicology, Research and Teaching Program (GC), by a NICHD Training Grant (AH) T32 HD071131, “Fertilization and Early Development” and by the National Sea Grant Program, National Oceanic and Atmospheric Administration, US Department of Commerce under project number R/CZ-182 through the California Sea Grant College (DE). The views expressed herein are those of the authors and do not necessarily reflect the views of NOAA or any of its subagencies. The US government is authorized to reproduce and distribute for governmental purposes. BML contribution number 2217.

PY - 2004/12/15

Y1 - 2004/12/15

N2 - This study presents functional and molecular evidence for acquisition of multidrug transporter-mediated efflux activity as a consequence of fertilization in the sea urchin. Sea urchin eggs and embryos express low levels of efflux transporter genes with homology to the multidrug resistance associated protein (mrp) and permeability glycoprotein (p-gp) families of ABC transporters. The corresponding efflux activity is low in unfertilized eggs but is dramatically upregulated within 25 min of fertilization; the expression of this activity does not involve de novo gene expression and is insensitive to inhibitors of transcription and translation indicating activation of pre-existing transporter protein. Our study, using specific inhibitors of efflux transporters, indicates that the major activity is from one or more mrp-like transporters. The expression of activity at fertilization requires microfilaments, suggesting that the transporters are in vesicles and moved to the surface after fertilization. Pharmacological inhibition of mrp-mediated efflux activity with MK571 sensitizes embryos to the toxic compound vinblastine, confirming that one role for the efflux transport activity is embryo protection from xenobiotics. In addition, inhibition of mrp activity with MK571 alone retards mitosis indicating that mrp-like activity may also be required for early cell divisions.

AB - This study presents functional and molecular evidence for acquisition of multidrug transporter-mediated efflux activity as a consequence of fertilization in the sea urchin. Sea urchin eggs and embryos express low levels of efflux transporter genes with homology to the multidrug resistance associated protein (mrp) and permeability glycoprotein (p-gp) families of ABC transporters. The corresponding efflux activity is low in unfertilized eggs but is dramatically upregulated within 25 min of fertilization; the expression of this activity does not involve de novo gene expression and is insensitive to inhibitors of transcription and translation indicating activation of pre-existing transporter protein. Our study, using specific inhibitors of efflux transporters, indicates that the major activity is from one or more mrp-like transporters. The expression of activity at fertilization requires microfilaments, suggesting that the transporters are in vesicles and moved to the surface after fertilization. Pharmacological inhibition of mrp-mediated efflux activity with MK571 sensitizes embryos to the toxic compound vinblastine, confirming that one role for the efflux transport activity is embryo protection from xenobiotics. In addition, inhibition of mrp activity with MK571 alone retards mitosis indicating that mrp-like activity may also be required for early cell divisions.

KW - Activation

KW - Calcein-am

KW - Embryo

KW - Fertilization

KW - Mitosis

KW - Multidrug efflux

KW - SpABCB1

KW - SpABCC1

KW - SpABCC2

KW - mk571

KW - mrp

KW - p-gp

KW - psc833

UR - https://www.scopus.com/pages/publications/9944225330

UR - https://www.scopus.com/pages/publications/9944225330#tab=citedBy

U2 - 10.1016/j.ydbio.2004.09.013

DO - 10.1016/j.ydbio.2004.09.013

M3 - Article

C2 - 15581878

SN - 0012-1606

VL - 276

SP - 452

EP - 462

JO - Developmental biology

JF - Developmental biology

IS - 2

ER -