LIM homeobox genes are well conserved in evolution and play important roles as transcriptional regulators of embryonic development. Here we report on the structure of LIM domains of the mouse Lhx4 (Gsh4) gene. The cDNA was generated by modified reverse transcription-PCR from midgestation embryo templates, using a degenerate consensus primer. The deduced amino acid sequence of the first LIM domain reveals 77% identity and that of the second domain reveals 86% identity with the corresponding sequences of the closely related Lhx3 gene. In addition, there is 38-56% similarity to other members of the Lhx gene family. The LIM consensus sequence is well conserved in Lhx4.