Mutation (IMAGE) University of the Basque Country Caption A mutation of amino acid 144 of the UPSP21 protein (which has over 500 amino acids) causes this protein to accumulate in the nucleus of a cell instead of remaining outside. The image, obtained by means of fluorescent microscopy, shows the protein in green and the cell nucleus in blue. Credit UPV/EHU Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.