| With the development of the times and the improvement of material level,food nutrition and health are paid more and more attention.As an essential trace element,Zinc can't be synthesized by ourselves,but only can be taken from diet.Zinc participates in so many important life activities in the body that the balance of zinc is closely related to human health.With the development of society and the improvement of people's health awareness,functional food which has reasonable nutrition and health care caused widespread concern in the community.However,The development of functional food needs people's deep understanding of physiology and nutrition as the basis.Therefore,to explore the molecular mechanism of zinc ion homeostasis is not only of far-reaching significance for the prevention and treatment of diseases that related to zinc metabolism disorder,but also of far-reaching significance for the research and development of related functional foods.In order to maintain the health of the body,zinc ion must maintain a stable state,which is directly affected by the absorption,excretion and reabsorption of zinc ion.In mammals,two family proteins of zinc transporters SLC39A(Zip)and SLC30A(Zn T)are directly involved in the transport of zinc ions in cells,which are important for maintaining zinc homeostasis.There are many studies on the absorption of zinc ions,and the mechanism is well understood.However,there are few reports on the excretion mechanism of zinc ions.Catsup is an inhibitor of dopamine synthesis pathway found in Drosophila.Many studies have shown that Catsup is related to reproduction and sleep,but its molecular function is not clear.We use bioinformatics to predict that Catsup is likely to be a zinc transporter,but whether it participates in zinc metabolism and how it affects zinc metabolism need to be studied.In this project,we use the Drosophila model to study and find that Catsup is a member of the ZIP family located on Golgi body,belonging to the homologous substance of human zinc transport protein h Zip7,which is involved in zinc excretion in the hindgut of Drosophila.Our results show that:(1)Catsup was transfected into CHO cells.By ALP activity assay and zrt-1 promoter reporter gene assay,it was found that the level of zinc in the cytoplasm increased and that in Golgi body decreased,which proved that Catsup was a zinc transporter,responsible for transporting zinc ions into the cytoplasm.The localization of Catsup on Golgi body was proved by immunohistochemistry.Through genetic experiments,it was found that h Zip7 could save the growth defects of Catsup RNAi Drosophila.In conclusion,Catsup is a zinc transporter located on Golgi apparatus,and it is a homolog of h Zip7.(2)After specifically knocking down Catsup in the hindgut,the eclosion rate of Drosophila decreased significantly and was sensitive to zinc ions,which indicated that Catsup expressed in the hindgut was necessary for growth and development,and was related to zinc homeostasis.(3)After specifically knocking down Catsup in the hindgut,the level of zinc in the hindgut and the Malpighian tube decreased,but the level of zinc in the body increased,indicating that Catsup is responsible for the discharge of zinc ions from the body to the hindgut and the Malpighian tube,and then out of the body.(4)A series of phenotypes caused by Catsup knockdown in the hindgut can be regulated by Zn T1 or Zip1.Furthermore,we have proved that Zn T1 and Zip1 affect zinc homeostasis in the hindgut.To sum up,we found that the hindgut and Malpighian tubes of Drosophila have the function of zinc ion excretion and reabsorption,similar to human kidney.At the same time,Catsup participates in zinc ion excretion in the hindgut,Zip1 and Zn T1 have the function of maintaining zinc homeostasis in the hindgut.This work enriches the excretion mechanism of zinc ions,lays a foundation for better understanding of zinc metabolism and regulation of zinc homeostasis,and provides a new clue for the development of related functional foods. |
PDF Full Text Request