Cloning and analysis of axolotl ISL2 and LHX2 LIM-homeodomain transcription factors.
We cloned and characterized the ISL2 and LHX2 LIM-homeodomain transcription factors of the Mexican salamander, or axolotl, Ambystoma mexicanum. Using a degenerate PCR approach, partial cDNAs representing five LIM-homeodomain genes were cloned, indicating conservation of this class of transcription factors in urodeles. Full-length cDNAs for Isl2 and Lhx2 were identified and sequenced. The predicted ISL2 and LHX2 proteins are well conserved, especially in the LIM and DNA-binding domains. The Isl2 and Lhx2 genes are expressed at all examined stages of embryogenesis and display tissue-restricted expression patterns in adults. In functional tests, axolotl LHX2 was inactive compared to homologous mammalian factors and adopted unusual DNA/protein complexes. However, axolotl ISL2 bound and induced transcription from the rat insulin gene. These experiments demonstrate conservation of key developmental regulatory proteins in salamanders and will allow future studies of their potential roles in the molecular regulation of tissue regeneration in such species.
Showalter
Aaron D
AD
Department of Biology and Indiana University Center for Regenerative Biology and Medicine, School of Science, Indiana University-Purdue University Indianapolis (IUPUI), Indianapolis, Indiana 46202-5132, USA.
Yaden
Benjamin C
BC
Chernoff
Ellen A G
EA
Rhodes
Simon J
SJ
D000818:Animals; D002478:Cells, Cultured; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D024202:Electrophoretic Mobility Shift Assay; D005314:Embryonic and Fetal Development / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000502:physiology*; D006801:Humans; D060850:LIM-Homeodomain Proteins; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D009419:Nerve Tissue Proteins / Q000502:physiology*; D016133:Polymerase Chain Reaction; D014176:Protein Biosynthesis; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic
D018076:DNA, Complementary; D018398:Homeodomain Proteins; C558561:Isl2 protein, mouse; C558562:Isl2 protein, rat; C489783:LHX2 protein, human; D060850:LIM-Homeodomain Proteins; C489784:Lhx2 protein, mouse; D009419:Nerve Tissue Proteins; D014157:Transcription Factors; C063843:insulin gene enhancer binding protein Isl-1; D008156:Luciferases