Human profilin. Molecular cloning, sequence comparison, and chromosomal analysis.

Area of Science:

• Molecular Biology
• Cell Biology
• Genetics

Background:

• Profilin is an essential actin monomer-binding protein found across species.
• Previous studies identified two profilin isoforms in Acanthamoeba.
• Human profilin's genetic basis and tissue distribution were not fully elucidated.

Purpose of the Study:

• To isolate and characterize human profilin cDNA.
• To investigate the existence of multiple human profilin isoforms.
• To determine the tissue distribution and genetic loci of human profilin.

Main Methods:

• Isolation of full-length profilin cDNA clones from a human HepG2 library.
• Northern blot and RNase protection analyses of human tissues.
• Southern blot analysis of human genomic DNA.

Main Results:

• A single nucleotide sequence for human profilin cDNA was identified.
• Northern blot analysis revealed a uniform approximately 850-base message across all human tissues, with no evidence of alternative splicing.
• Human profilin shares 90% amino acid identity with bovine profilin.
• Southern blot analysis identified at least four dispersed genetic loci for profilin in the human genome, suggesting pseudogenes.
• Conserved 5' and 3' untranslated regions between human and rodent profilin genes were observed.

Conclusions:

• Human cells likely express a single profilin isoform.
• Profilin is widely distributed in human epithelial, muscle, and renal tissues.
• The human profilin gene has multiple loci, including pseudogenes, and conserved untranslated regions suggest functional importance.