An alternative internal splicing site defines new Ikaros isoforms in Pleurodeles waltl.
The Ikaros gene encodes a family of transcription factors which plays a crucial role in hematopoiesis. To improve our knowledge about the immune system of Pleurodeles waltl, we sequenced the cDNA coding for the Ik-1 isoform of that salamander and analyzed its tissue expression by semi-quantitative RT-PCR. Ikaros transcripts are abundant in the thymus and the spleen, thereby confirming that these organs are, respectively, the primary and secondary lymphoid tissues of Pleurodeles. Analysis of the isoforms produced by this animal revealed two isoforms characteristic of amphibians in which an alternative internal splicing site deletes the 3' half of exon 3 which interestingly comprises the first Zn finger of Ikaros. Ikaros transcripts were found at the earliest stages of development of Pleurodeles indicating that Ikaros has a function at the very early lymphopoietic stages. Moreover, the presence of Ikaros transcripts in spermatozoa suggests that this protein could have another and yet unknown function.
Boudarra
Najia
N
Laboratoire de Biologie Expérimentale et Immunologie, UPRES EA 2401, Université Henri Poincaré, Nancy 1, Boulevard des Aiguillettes, BP 239, F-54506 Vandoeuvre-lès-Nancy Cedex, France.
Frippiat
Christophe
C
Dournon
Christian
C
Frippiat
Jean-Pol
JP
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D015870:Gene Expression; D006801:Humans; D051740:Ikaros Transcription Factor; D008969:Molecular Sequence Data; D010999:Pleurodeles / Q000235:genetics; D020033:Protein Isoforms / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014018:Tissue Distribution; D014157:Transcription Factors / Q000235:genetics*; D016335:Zinc Fingers
D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D020033:Protein Isoforms; D014157:Transcription Factors; D051740:Ikaros Transcription Factor