as a novel mark for labeling the proximal convoluted tubule within the zebrafish kidney.

The proximal convoluted tubule (PCT) of the kidney is a crucial functional segment responsible for reabsorption, secretion, and the maintenance of electrolyte and water balance within the renal tubule. However, there is a lack of a well-defined endogenous transgenic line for studying PCT morphogenesis. By analyzing single-cell transcriptome data from the adult zebrafish kidney, we have identified the expression of odd-skipped-related 2 (, which encodes an odd-skipped zinc-finger transcription factor) in the PCT. To gain insight into the role of in PCT morphogenesis, we have generated a transgenic zebrafish line , expressing enhanced green fluorescent protein (EGFP). The EGFP expression pattern closely mirrors that of endogenous Osr2, faithfully recapitulating its native expression profile. During kidney development, we can use EGFP to track PCT development, which is also preserved in adult zebrafish. Additionally, -labeled zebrafish PCT fragments displayed short lengths with infrequent overlap, rendering them conducive for nephrons counting. The generation of transgenic line is accompanied by simultaneous disruption of activity. Importantly, our findings demonstrate that inactivation had no discernible impact on the development and regeneration of zebrafish nephrons. Overall, the establishment of this transgenic zebrafish line offers a valuable tool for both genetic and chemical analysis of PCT.