CREB-family transcription factors and vasopressin-mediated regulation of gene transcription.

BACKGROUND

Water homeostasis is regulated by the peptide hormone arginine vasopressin (AVP), which promotes water reabsorption in the renal collecting duct. The regulation of gene transcription is a key mechanism through which AVP modulates water transport as disruption of this mechanism leads to water balance disorders. Therefore, an important goal is to understand the regulatory processes that control gene transcription. While CREB (CREB1) has been proposed as the primary transcription factor responsible for transcription, recent evidence challenges this view, suggesting that other CREB-like transcription factors, including ATF1 and CREM, may play a role.

METHODS

We employed the CRISPR/Cas9 gene-editing system to delete , , and in mpkCCD cells, an immortalized mouse collecting duct cell line. These cell lines were then exposed to the vasopressin analog, dDAVP, to assess the role of these transcription factors in regulating expression. AQP2 protein levels were measured by immunoblotting and RNA-seq was used to analyze changes in mRNA abundance, as well as other transcriptomic changes.

RESULTS

Deletion of all three transcription factors (ATF1, CREB1, and CREM) led to a significant reduction in the vasopressin-induced upregulation of AQP2 protein, confirming their role in regulating expression. RNA-seq data showed that mRNA levels mirrored changes in protein abundance, supporting the idea that these transcription factors affect transcription. Rescue experiments in triple knockout cells showed that expressing any of the three transcription factors restored the response to vasopressin.

CONCLUSIONS

Our findings demonstrate that ATF1, CREB1, and CREM have redundant roles in regulating transcription. Based on these results and prior data, we propose that these CREB-family transcription factors may regulate gene transcription indirectly by controlling the expression of additional unidentified transcription factors.