This may help us learn how proteins cross biological membranes. Delineation and mutational analysis of the Yersinia pseudotuberculosis YopE domains which mediate translocation across bacterial and eukaryotic cellular membranes. Transgenic Model of Imprinted Gene Genomic imprinting is the differential expression of alleles of a gene depending on the parental origin. How imprinting is controlled is not known. Fewer than 20 genes are known to undergo imprinting.
Imprinted genes are functionally haploid, and therefore extra vulnerable to mutation.
Prader-Willi syndrome and Angelman syndrome involve imprinted genes. Marisa S. Bartolomei and David A. Elson of the Howard Hughes Medical Institute and University of Pennsylvania School of Medicine created a transgene harboring the elements hypothesized to be important for imprinted expression. They found that the transgene is expressed very similarly to the endogenous gene. Once we completely understand those sequences that target the imprinting apparatus and what the imprinting modification is, we hope to determine where, when, and how the imprint is determined. A 5' differentially methylated sequence and the 3'-flanking region are necessary for H19 transgene imprinting.