Compositional properties and codon usage of TP73 gene family.

The TP73 gene is considered as one of the members of TP53 gene family and shows much homology to p53 gene. TP73 gene plays a pivotal role in cancer studies in addition to other biological functions. Codon usage bias (CUB) is the phenomenon of unequal usage of synonymous codons for an amino acid wherein some codons are more frequently used than others and it reveals the evolutionary relationship of a gene. Here, we report the pattern of codon usage in TP73 gene using various bioinformatic tools as no work was reported yet. Nucleotide composition analysis suggested that the mean nucleobase C was the highest, followed by G and the gene was GC rich. Correlation analysis between codon usage and GC3 suggested that most of the GC-ending codons showed positive correlation while most of the AT-ending codons showed negative correlation with GC3 in the coding sequences of TP73 gene variants in human. The CUB is moderate in human TP73 gene as evident from intrinsic codon deviation index (ICDI) analysis. Nature selected against two codons namely ATA (isoleucine) and AGA (arginine) in the coding sequences of TP73 gene during the course of evolution. A significant correlation (p < 0.05) was found between overall nucleotide composition and its composition at the 3rd codon position, indicating that both mutation pressure and natural selection might influence the CUB. The correlation analysis between ICDI and biochemical properties of protein suggested that variation of CUB was associated with degree of hydrophobicity and length of protein.