Genetics of the large, external, transformation-sensitive (LETS) protein: assignment of a gene coding for expression...

Techniques have been developed to analyze the genetics of the large, external, transformation-sensitive (LETS) protein (fibronectin). External membrane proteins of human-mouse somatic cell hybrids with reduced numbers of human but not mouse chromosomes were labeled by lactoperoxidase-catalyzed iodination. Cell surface proteins were identified after sodium dodecyl sulfate/polyacrylamide gel electrophoresis by autoradiography of the dried gel. The LETS protein was identified in parental human cells, and LETS segregated in human-mouse cell hybrids formed from human WI-38 fibroblasts and a mouse L-cell line not expressing LETS. The LETS protein segregated concordantly with the chromosome 8 enzyme marker glutathione reductase (EC 1.6.4.2) and human chromosome 8. These findings demonstrate that a gene, LETS, encoded on chromosome 8, is responsible for the LETS protein expression in humans. Because LETS has been implicated in tumorigenicity and cellular transformation, it is of interest that rearrangement or modifications in the number of chromosome 8 have been associated with certain forms of cancer.