title: Expression of multiple glutamate transporter splice variants in the rodent testis.
abstract: Glutamate is a regulated molecule in the mammalian testis. Extracellular regulation of glutamate in the body is determined largely by the expression of plasmalemmal glutamate transporters. We have examined by PCR, western blotting and immunocytochemistry the expression of a panel of sodium-dependent plasmalemmal glutamate transporters in the rat testis. Proteins examined included: glutamate aspartate transporter (GLAST), glutamate transporter 1 (GLT1), excitatory amino acid carrier 1 (EAAC1), excitatory amino acid transporter 4 (EAAT4) and EAAT5. We demonstrate that many of the glutamate transporters in the testis are alternately spliced. GLAST is present as exon-3- and exon-9-skipping forms. GLT1 was similarly present as the alternately spliced forms GLT1b and GLT1c, whereas the abundant brain form (GLT1a) was detectable only at the mRNA level. EAAT5 was also strongly expressed, whereas EAAC1 and EAAT4 were absent. These patterns of expression were compared with the patterns of endogenous glutamate localization and with patterns of d-aspartate accumulation, as assessed by immunocytochemistry. The presence of multiple glutamate transporters in the testis, including unusually spliced forms, suggests that glutamate homeostasis may be critical in this organ. The apparent presence of many of these transporters in the testis and sperm may indicate a need for glutamate transport by such cells.
authors.affiliation: Centre for Clinical Research, Royal Brisbane and Women’s Hospital, The University of Queensland, Brisbane, Qld 4029, Australia.
authors.forename: Aven
authors.initials: A
authors.lastname: Lee
authors.forename: Ashley R
authors.initials: AR
authors.lastname: Anderson
authors.forename: Amanda C
authors.initials: AC
authors.lastname: Barnett
authors.forename: Anthony
authors.initials: A
authors.lastname: Chan
authors.forename: David V
authors.initials: DV
authors.lastname: Pow
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D027322:Amino Acid Transport System X-AG / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D001483:Base Sequence; D001921:Brain / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D027342:Excitatory Amino Acid Transporter 2 / Q000235:genetics / Q000378:metabolism; D050580:Excitatory Amino Acid Transporter 3 / Q000235:genetics / Q000378:metabolism; D050581:Excitatory Amino Acid Transporter 4 / Q000235:genetics / Q000378:metabolism; D050582:Excitatory Amino Acid Transporter 5 / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D018698:Glutamic Acid / Q000378:metabolism; D006706:Homeostasis; D007150:Immunohistochemistry; D008297:Male; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D012160:Retina / Q000378:metabolism; D013737:Testis / Q000378:metabolism*
chemical_list: D027322:Amino Acid Transport System X-AG; D017931:DNA Primers; D027342:Excitatory Amino Acid Transporter 2; D050580:Excitatory Amino Acid Transporter 3; D050581:Excitatory Amino Acid Transporter 4; D050582:Excitatory Amino Acid Transporter 5; D012333:RNA, Messenger; C493398:Slc1a1 protein, rat; D001224:Aspartic Acid; D018698:Glutamic Acid