Cloning, structural analysis, and chromosomal localization of the human CSRP2 gene encoding the LIM domain protein CRP2.

The CSRP2 gene encoding the LIM domain protein CRP2 was originally identified in quail based on its strong transcriptional suppression in transformed avian fibroblasts. Here we have isolated a human CSRP2 cDNA clone encoding a 193-amino-acid human CRP2 (hCRP2) protein with 96.4% amino acid sequence identity to the avian homolog. The CSRP2 cDNA clone was used to isolate CSRP2-related clones from gamma EMBL3 and P1 libraries of human genomic DNA. The complete organization of the CSRP2 gene was determined by nucleic acid hybridization, transcriptional mapping, and nucleotide sequence analysis. The gene spans a total of approximately 22 kb and contains six exons. The coding region is confined to exons 2-6 and predicts a hCRP2 protein identical in its amino acid sequence to the protein deduced from the CSRP2 cDNA clone. By fluorescence in situ hybridization using both lambda EMBL3 and P1 library clones as hybridization probes and a new method for computerized signal localization, CSRP2 was mapped to chromosome subband 12q21.1, a region frequently affected by deletion or breakage events in various tumor types. The library screens also led to the isolation of a CSRP2-related pseudogene, CSRP2P, which carried several extensive deletions and nucleotide substitutions but no intervening sequences in comparison to the CSRP2 cDNA sequence. By physical linkage and fluorescence in situ hybridization, CSRP2P was mapped to chromosome subband 3q21.1.