GATA3 mRNA in ginbuna crucian carp (Carassius auratus langsdorfii):: cDNA cloning, splice variants and expression analysis

GATA3, a transcriptional activator, plays a critical rote in the development of T-cells and differentiation to T helper type 2 cells. To date, no information is available on the role of GATA3 in the teleost immune system. We identified full-length cDNA and alternatively spliced variants of ginbuna crucian carp GATA3 (gbGATA3). The gbGATA3 gene is transcribed into multiple splice variants lacking either one or both zinc finger domains, although the sequences of both domains are fully conserved between ginbuna and other vertebrates. We found that alternative splice site and stop codon in gbGATA3 intron 3, located between exons that separately encode the two zinc finger domains, are conserved among teleosts, suggesting that teleost GATA3 gene can be translated into multiple isoforms. RT-PCR analysis revealed that the gbGA7A3 is strongly expressed in the brain, thymus and gill of unstimulated fish. Moreover, gbGATA3 expression was detected in surface-IgM- negative lymphocytes among kidney cells sorted by FACS. Real-time PCR demonstrated that expression levels of full-length gbGATA3 and the splice variants differed with tissue type, but full length was always the predominantly expressed form. These results suggest that gbGATA3, including its splice variants, is involved in teteost T-cell function. (C) 2008 Elsevier Ltd. All rights reserved.