Specific Expression and Regulation of Glucose Transporters in Zebrafish Ionocytes

Tseng, Y.C., Chen, R.D., Lee, J.R., Liu, S.T., Lee, S.J., and Hwang, P.P.
American journal of physiology. Regulatory, integrative and comparative physiology   297(2): R275-R290 (Journal)
Registered Authors
Hwang, Pung Pung, Lee, Shyh-Jye, Tseng, Yung-Che
MeSH Terms
  • Acclimatization/genetics
  • Amino Acid Sequence
  • Animal Structures/metabolism
  • Animals
  • Calcium/pharmacology
  • Chlorides/pharmacology
  • Cloning, Molecular
  • DNA, Complementary/genetics
  • Epithelial Cells/metabolism*
  • Forkhead Transcription Factors/genetics
  • Gene Expression/drug effects
  • Gene Expression/genetics
  • Gene Expression Regulation*
  • Gene Expression Regulation, Developmental/physiology
  • Gene Order/genetics
  • Gills/cytology*
  • Gills/metabolism
  • Glucose Transport Proteins, Facilitative/chemistry
  • Glucose Transport Proteins, Facilitative/genetics
  • Glucose Transport Proteins, Facilitative/metabolism*
  • Larva/metabolism
  • Membrane Proteins/chemistry
  • Molecular Sequence Data
  • Oligonucleotides, Antisense/genetics
  • Phylogeny
  • Protein Isoforms/genetics
  • Protein Structure, Tertiary/genetics
  • Sequence Homology, Amino Acid
  • Skin/metabolism
  • Sodium/pharmacology
  • Zebrafish/genetics
  • Zebrafish/metabolism*
  • Zebrafish Proteins/chemistry
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism*
19458281 Full text @ Am. J. Physiol. Regul. Integr. Comp. Physiol.
Glucose, a carbohydrate metabolite, plays a major role in the energy supply for fish iono- and osmoregulation, and the way that glucose is transported in ionocytes is a critical process related to the functional operations of ionocytes. Eighteen members of glucose transporters (GLUTs, SLC2A) were cloned and identified from zebrafish. Previously, Na(+),K(+)-ATPase-rich (NaR), Na(+)-Cl(-) cotransporter-expressing (NCC), H(+)-ATPase-rich (HR), and glycogen-rich (GR) cells have identified to be responsible for Ca(2+) uptake, Cl(-) uptake, Na(+) uptake, and the energy deposition, respectively, in zebrafish skin/gills. The purpose of the present study was to test the hypothesis of whether GLUT isoforms are specifically expressed and function in ionocytes to supply energy for ion regulatory mechanisms. Based on translational knockdown of foxi3a/3b (2 transcriptional factors related to the ionocytes' differentiation) and triple in situ hybridization/immunocytochemistry, 3 GLUT isoforms, zglut1a, -6, and -13.1, were specifically localized in NaR/NCC cells, GR cells, and HR cells, respectively. mRNA expression of zglut1a in embryos and adult gills were stimulated by the low Ca(2+) or low Cl(-) freshwater, which has been previously reported to respectively upregulate the functions (monitored by epithelial Ca(2+) channel, NCC mRNA) of NaR/NCC cells, while that of zglut13.1 was stimulated only by low Na(+), a situation to upregulate the function (monitored by carbonic anhydrase 15a mRNA) of HR cells. On the other hand, ambient ion compositions did not affect the zglut6 mRNA expression. Taken together, zGLUT1a, -6, and 13.1, the specific transporters in NaR/NCC cells, GR cells, and HR cells, may absorb glucose into the respective cells to fulfill different physiological demands. Key words: mitochondrion-rich cells, ion transport, environment, adaptation, epithelium.
Genes / Markers
Mutation and Transgenics
Human Disease / Model Data
Sequence Targeting Reagents
Engineered Foreign Genes
Errata and Notes