Protein 4.1 is an important structural protein that is expressed in erythroid and in a variety of nonerythroid tissues. In mammalian erythrocytes, it plays a key role in regulating the physical properties of mechanical stability and deformability in membranes by stabilizing the spectrin-actin interaction. The protein 4.1 family mainly comprises 4.1R, 4.1G (general type), 4.1B (brain type), and 4.1N (neuron type). We identified a novel human 4.1 ( 4.1O) gene that is 2312 bp in length and encodes a protein of 553 amino acid residues. The protein shared homology with mouse protein 4.1B (identity 38%, similarity 55%) with a FERM domain. The expression pattern of the human 4.1O gene in 16 tissues showed that there was a transcript only in ovary, whereas in the remaining 15 tissues, specific bands of the transcript could not be detected. In eight human fetal tissues, the specific bands of the transcript could be detected in skeletal muscle, with lower levels detected in thymus and brain. The 4.1O gene consists of 14 exons and 13 introns and was mapped to Chromosome 9q21-9q22 by bioinformatics analysis.