Fragile X Mental Retardation Syndrome Related Protein 1 (FXR1)

FXR1 is an RNA binding protein that interacts with the functionally-similar proteins FMR1 and FXR2. These proteins shuttle between the nucleus and cytoplasm and associate with polyribosomes, predominantly with the 60S ribosomal subunit. Three transcript variants encoding different isoforms have been found for this gene.

This cDNA was then used to screen a HeLa cell library. They identified a cDNA that encodes a predicted protein of 621 amino acids. The gene, designated FXR1 (FMR1 cross-reacting relative) by them, shows 86% amino acid sequence identity to the KH RNA binding domains of FMR1 and 70% identity over the amino-terminal domain. However, the carboxyl domains are entirely unrelated. RT-PCR analysis showed that many cell types express FXR1 mRNA.