Zebrafish homologue irx1a is required for the differentiation of serotonergic neurons.

Serotonergic (5HT) neurons produce neurotransmitter serotonin, which modulates various neuronal circuits. The specification and differentiation of 5HT neurons require both extrinsic signals such as Shh and Fgf, as well as intrinsic transcription factors such as nkx2.2, mash1, phox2b, Gata2, and pet1.

The homeobox gene irx1a is required for the propagation of the neurogenic waves in the zebrafish retina.

Neurogenesis in the compound eyes of Drosophila and the camera eyes of vertebrates spreads in a wave-like fashion. In both phyla, waves of hedgehog expression are known to drive the wave of neuronal differentiation. The mechanism controlling the propagation of hedgehog expression during retinogenesis of the vertebrate eye is poorly understood.

Cloning of zebrafish metallothionein gene and characterization of its gene promoter region in HepG2 cell line.

The coding region of cDNA and genomic DNA, with its promoter region, of zebrafish metallothionein (zMT) gene homologous to the piscine MT-II was obtained. The A/T-rich promoter region contains four metal regulatory elements (MREs), three activator protein 1 (AP1) and one specific protein 1 (Sp1) binding sites. The four MREs are organized into two clusters, a distal cluster with one MRE lying around 740 bp upstream of the transcription start point and a proximal cluster with three MREs located close to the TATA box.

Characterization of zebrafish metallothionein gene promoter in a zebrafish caudal fin cell-line, SJD. 1.

Metallothioneins (MTs) are low molecular weight metal binding proteins that are implicated in heavy metal detoxification processes, and their quantification are commonly used as biomarkers of exposure to heavy metal ions. To verify the use of zebrafish MT gene promoter for aquatic toxicology studies, an 835 bp zebrafish MT (zMT) gene promoter with four putative metal regulatory elements (MREs) was isolated by DNA walking method and characterized for metal induction of gene transcription using transient expression assays in a zebrafish caudal fin cell line, SJD.1.