bloodthirsty, an RBCC/TRIM gene required for erythropoiesis in zebrafish

Dev Biol. 2005 Jul 1;283(1):97-112. doi: 10.1016/j.ydbio.2005.04.006.


The Antarctic icefishes (family Channichthyidae, suborder Notothenioidei) constitute the only vertebrate taxon that fails to produce red blood cells. These fishes can be paired with closely related, but erythrocyte-producing, notothenioids to discover erythropoietic genes via representational difference analysis. Using a B30.2-domain-encoding DNA probe so derived from the hematopoietic kidney (pronephros) of a red-blooded Antarctic rockcod, Notothenia coriiceps, we discovered a related, novel gene, bloodthirsty (bty), that encoded a 547-residue protein that contains sequential RING finger, B Box, coiled-coil, and B30.2 domains. bty mRNA was expressed by the pronephric kidney of N. coriiceps at a steady-state level 10-fold greater than that found in the kidney of the icefish Chaenocephalus aceratus. To test the function of bty, we cloned the orthologous zebrafish gene from a kidney cDNA library. Whole-mount in situ hybridization of zebrafish embryos showed that bty mRNA was present throughout development and, after the mid-blastula transition, was expressed in the head and in or near the site of primitive erythropoiesis in the tail just prior to red cell production. One- to four-cell embryos injected with two distinct antisense morpholino oligonucleotides (MOs) targeted to the 5'-end of the bty mRNA failed to develop red cells, whereas embryos injected with 4- and 5-bp mismatch control MOs produced wild-type quantities of erythrocytes. The morphant phenotype was rescued by co-injection of synthetic bty mRNA containing an artificial 5'-untranslated region (UTR) with the antisense MO that bound the 5'-UTR of the wild-type bty transcript. Furthermore, the expression of genes that mark terminal erythroid differentiation was greatly reduced in the antisense-MO-treated embryos. We conclude that bty is likely to play a role in differentiation of the committed red cell progenitor.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Carrier Proteins / chemistry
  • Carrier Proteins / genetics*
  • Cell Differentiation
  • DNA Primers
  • DNA, Complementary / genetics
  • Embryo, Nonmammalian / physiology*
  • Erythropoiesis / physiology*
  • Gene Expression Regulation, Developmental*
  • In Situ Hybridization
  • Molecular Sequence Data
  • Polymerase Chain Reaction
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Species Specificity
  • Transcription, Genetic
  • Zebrafish / embryology*
  • Zebrafish Proteins / chemistry
  • Zebrafish Proteins / genetics*


  • Carrier Proteins
  • DNA Primers
  • DNA, Complementary
  • Zebrafish Proteins
  • bty protein, zebrafish