A complementary DNA (1392 bp) encoding a protein with high homology to rat reversion-induced LIM (RIL) protein was cloned from rat hepatocytes by differential screening of a subtractive (normoxic minus hypoxic) λGEM-2 cDNA library. This cDNA clone, denoted CLP-36, encodes a 327-amino-acid (aa) protein that contained a restrictively conserved LIM (a Cys-rich domain with consensus aa sequence C-X2-C-X17-19-H-X2-C-X2-C-X2-C-X16-20-C-X2-C/ H/D that was initially identified in homeodomain proteins, Lin-11 [Freyd et al., Nature 344 (1990) 876-879], Isl-1 [Karlsson et al., Nature 344 (1990) 879-882] and Mec-3 [Way et al., Cell 54 (1988) 5-16] in the C-terminal portion (aa 192-327). It shared an overall 45.1% identity to a rat LIM domain RIL protein [Kiess et al., Oncogene 10 (1995) 61-68], with 62.0% identity in the N terminus (aa 1-89) and 50.0% identity in the C terminus (aa 188-327). The rat CLP-36 mRNA is expressed most abundantly in heart, lung and liver, moderately in spleen and skeletal muscle, and at extremely low levels (if at all) in testis and brain tissues. Northern blotting analysis of total RNA extracted from normoxic or hypoxic rat hepatocytes, with a fragment of clone CLP-36 as probe, demonstrated a single band with a mobility corresponding to a size of 1.4 kb, whose level was significantly decreased during chemical hypoxia.
Bibliographical noteFunding Information:
We thank Dr. W. Litaker of the Biotechnology Center of University of North Carolina for his valuable discussions, and Drs. A. Periasamy, G. Gordon and P. Wodnicki for their expert assistance in using computer for DNA database analysis. This research was supported by grant AG07218 from NIH to B.H.
- amino-acid sequence
- chemical hypoxia
- nucleotide sequence
- phage library
- recombinant DNA