Differential Expression of Genes Responsible for Reproduction of Male and Female Danio rerio Following Interaction Between Estrogen Receptor and Cadmium

• Published in: Proceedings of the Zoological Society Vol. 74; no. 4; pp. 456 - 465
• Main Authors: Roy, Dola, Mitra, Anisa, Homechaudhuri, Sumit
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New Delhi Springer India 01.12.2021; Springer Nature B.V
• Subjects: Animal Anatomy; Animal Genetics and Genomics; Aromatase; Binding sites; Biodiversity; Biomedical and Life Sciences; Cadmium; Chronic exposure; Conservation Biology/Ecology; Contaminants; Danio rerio; Environmental degradation; Estrogen receptors; Estrogens; Gene expression; Heavy metals; Histology; Isoforms; Life Sciences; Metal ions; Morphology; Polymerase chain reaction; Research Article; RNA-directed DNA polymerase; Vitellogenin; Zoology; Cadmium; Estrogen receptor; Zebrafish; Vitellogenin; Aromatase; Heavy metal
• ISSN: 0373-5893; 0974-6919
• DOI: 10.1007/s12595-021-00395-1

Environmental degradation due to anthropogenic contaminants, particularly the heavy metals are the major concern behind the disappearance of Small Indigenous Fishes (SIFs) from their natural habitats. The present study was aimed to comprehend the underline causes of disappearance of SIFs from their native habitat due to heavy metal by using the environmentally relevant dose of cadmium (Cd) on reproductive potential of zebrafish ( Danio rerio ) as a model SIF. For this purpose, the effects of Cd exposure on the differential gene expression of aromatase ( cyp19b ), estrogen receptors ( erα, erβa, erβb ) and vitellogenin ( vtg1 ) were examined using Reverse Transcriptase Polymerase Chain Reaction (RTPCR) for both male and female fishes; also, the interaction between Cd and estrogen receptor protein were analysed using molecular docking method. The result of the present study showed that, chronic exposure Cd downregulates the expression of Aromatase gene in both male and female fishes by 1.9 and 2.04 folds respectively. The expression of erα was decreased significantly in the female fishes but in case of males the expression was found to be increased and eventually lead to an increased vitellogenin (vtg) expression. Unlike erα , the expression of both  erβ isoforms, i.e.  erβa and erβb , were found to be significantly upregulated in female fishes and eventually they lead to decreased 1.33 fold vtg production. The in-silico study revealed that Estrogen receptor possess several metal-ion binding sites such as GLU 74, SER 144, SER150, HIS 185, HIS 190, GLU 188, ASP 280, TYR 287 and ASP 318, among them Cd actively interacts with HIS 190, HIS 185 and blocks the estrogen hormone binding site on the receptor protein. In conclusion, our results revealed that Cd as a potent endocrine disruptor can cause long term changes to the reproductive axis of both male and female  D. rerio leading to lower reproductive potential.