Molecular cloning and developmental expression of zinc finger transcription factor MTF-1 gene in zebrafish, Danio rerio.

Metal-responsive transcription factor, MTF-1 is a zinc finger protein, shown to be essential for embryonic development. Homozygous knockout mouse embryos for MTF-1 die in utero at day 14 of gestation, due to liver decay. In the present study, we report the complete nucleotide sequence of cDNA encoding zebrafish MTF-1 and the amino acid sequence similarity with that of mouse, human, fish and Drosophila. The size of the zebrafish MTF-1 cDNA is 3,379 bp and the coding region (1,779 bp) encodes a polypeptide of 593 amino acids. The putative zinc finger and transactivation domains comprised by zebrafish MTF-1 were also determined. The zebrafish MTF-1 shows high identity of 97, 93, 93 and 67% in the DNA binding zinc finger domain and 51, 44, 48 and 20% overall identity with fugu, human, mouse and Drosophila, respectively. RT-PCR results show the maternal expression of MTF-1 transcripts. The pattern of MTF-1 gene expression during embryonic and early larval development was studied by whole-mount in situ hybridization using DIG-labeled anti-sense RNA probe. Stronger and ubiquitous expression was observed during the embryonic stages whereas, specific expression, especially in the neural parts, was observed throughout the stages studied after hatching.