Characterization of the isoforms of MOVO zinc finger protein, a mouse homologue of Drosophila Ovo, as transcription factors.
We previously described two isoforms (MOVO-A and -B) of a novel zinc finger protein MOVO, a mouse homologue of Drosophila Ovo protein. Here, we isolated cDNA encoding the third isoform MOVO-C, which had a transactivation domain and zinc finger domain, but lacked an N-terminal potential repression domain that was present in MOVO-A. Three isoform mRNAs were expressed highly in mouse testis and also in the ovary at lower levels. The structural analyses of the isolated Movo gene and mRNAs demonstrated that three different Movo transcripts were differentially processed to generate three isoforms. Major mRNA species encoded MOVO-B with a zinc finger domain alone, and minor mRNA species encoded MOVO-A (potential repressor) and MOVO-C (potential activator). To assign MOVO to a transcriptional factor, we characterized DNA-binding and transactivation properties. Random oligonucleotide selection, electrophoretic mobility shift assay and footprinting indicated that MOVO bound to the sequence, 5'-G(G/C/T)GGGGG-3'. These motifs were found in the 5'-flanking regions of Movo and other testis-specific genes. Nuclear proteins binding to this motif were detected in mouse testis, and the expression of MOVO mRNA was restricted in spermatocytes. The luciferase assay demonstrated that MOVO-C activated Movo promoter and MOVO-A repressed it, but MOVO-B had no effects. Mutated MOVO-binding motifs in the Movo promoter reduced the luciferase activity. All the isoforms had no effects on SV40 promoter without MOVO-binding motifs. MOVO-A partially rescued oogenesis of a Drosophila ovo mutant. These results suggest that MOVO isoforms are transcription factors to regulate genes carrying the MOVO-binding motifs in the testis.
Unezaki
Sawako
S
Department of Medical Chemistry, Kansai Medical University, 10-15 Fumizono, Moriguchi, Osaka 570-8506 Japan.
Nishizawa
Mikio
M
Okuda-Ashitaka
Emiko
E
Masu
Yasuo
Y
Mukai
Masanori
M
Kobayashi
Satoru
S
Sawamoto
Kazunobu
K
Okano
Hideyuki
H
Ito
Seiji
S
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D019556:COS Cells; D002522:Chlorocebus aethiops; D004247:DNA / Q000737:chemistry / Q000235:genetics; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D004268:DNA-Binding Proteins / Q000235:genetics; D005260:Female; D020869:Gene Expression Profiling; D005796:Genes / Q000235:genetics; D005816:Genetic Complementation Test; D017403:In Situ Hybridization; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013737:Testis / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics*; D024363:Transcription Initiation Site; D015533:Transcriptional Activation; D016335:Zinc Fingers / Q000235:genetics*
D018076:DNA, Complementary; D004268:DNA-Binding Proteins; C491431:MOVO protein, mouse; D009687:Nuclear Proteins; C490318:Ovo1 protein, mouse; D020033:Protein Isoforms; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D004247:DNA; D008156:Luciferases