The Alteration of Tyrosine Phosphatase Gamma, Ptpg, and its Effect on Hematopoietic Differentiation
Katelynn Johnson and Amy Yanega, Franklin and Marshall College

Abstract
The formation of blood islands, which includes formation of blood cells and vessels in early embryos, hematopoietic differentiation, generally occurs around the third day of development. During gastrulation blood arises from the ventral mesoderm. Tyrosine phosphates are found early in hematopoietic tissue formation, which suggests their involvement in primary formation and development of blood islands. In this experiment we have blocked the expression of tyrosine phosphatase gamma (Ptpg) which is a member of the Tyrosine phosphate receptor group with the hopes of blocking the signaling pathway needed for the formation and development of the hematopoietic tissues. Two-day-old embryos were isolated and the expression of Ptpgwas blocked using antisense technology. The embryos were placed in an antisense solution which was made up of a liquid medium and containing either the an oligonucleotide that binds to the Ptpg gene and blocks its expression, the experimental solution, or the control solution, an oligonucleotide made up of a scrambled DNA sequence and therefore unable to bind Ptpg. After the embryos were exposed they remained untouched in an incubator for a few days. Finally when they were removed we discovered that when the expression of tyrosine phosphate gamma was blocked there was a significant decrease in blood cell and blood vessel formation. This finding supported our initial belief that tyrosine phosphate gamma (Ptpg) is an important player in blood cell and vessel formation.