Researchers in Shanghai Ocean University recently made important progresses in maaping the genetic circuitry that governing the cold responses in zebrafish.

As ectothermal animals, fishes are good models for studying stress response to environmental disturbances. A key to understand the process is to delineate the components of the genetic networks that govern the adaptive changes of gene expression.

Researchers first characterized the expression patterns of more than 20,000 genes of zebrafish at three different temperatures, and revealed 17 cis-regulatory elements in the upstream regions of more than 3000 genes that are cold responsive, which are partially attributable to the patterns of expressional changes of the harboring genes. Of the identified cis-elements, some are the binding sequence of known transcription factors, such as the AP-1 complex, and some are new and first discovered to be binding site for certain trans-factors. With functional verification of the cis- and trans-factor interacting pairs in vitro and in vivio, the researchers found that the transcription factor JUN joined by a transcriptional repressor BCL6 play a pivotal role in the regulation of cold responses in the regulatory network. Based on the interaction networks between the cis-elements and their corresponding trans-factors, the authors mapped a regulatory network of cold response in zebrafish. Through this network, one can understand the basic components which are involved in the regulation of cold responses in zebrafish. The network also serves a road map to uncover the evolution of these elements among fishes of different temperature regimes, thus to understand the mechanisms of molecular adaption to different temperatures by teleosts inhabiting the polar or tropical regions. The approach adopted in this study could also be suitable for deciphering the genetic circuitries that regulate fish adaptation to other environmental factors. 

The work has been published online on July 30, 2015 on Nucleic Acids Research. Prof. Chen Liangbiao from College of Fisheries and Life Science was the corresponding author and Dr. Hu Peng the first author of the article. Some master students in the research team also participated in this research. The study was supported by the Natural Science Foundation of China, the 973 Program and the First-class Discipline Development Programs on Aquaculture. The paper is available at: https://nar.oxfordjournals.org/content/early/2015/07/30/nar.gkv780.full