Mrp3, a mitogen-regulated protein/proliferin gene expressed in wound healing and in hair follicles

During cutaneous wound healing, a marked increase in the local expression o f growth factors results in increased migration and proliferation of the ce lls responsible for tissue repair. The mitogen-regulated protein (MRP)/prol iferin proteins are growth factors and angiogenesis factors. Here it is dem onstrated that Mrp3 is induced in wound edge keratinocytes during cutaneous wound healing and also temporally appears in the outer root sheath of the hair follicle during the late anagen phase of the hair cycle. In cultured k eratinocytes, Mrp3 is induced by keratinocyte growth factor, but not by epi dermal growth factor or by transforming growth factor type alpha. Transgeni c mice, expressing lacZ under the combined control of the cytomegalovirus i mmediate early enhancer and the Mrp3 flanking sequences, demonstrate wound- and hair cycle-induced transgene expression. These results show that eleme nts within the flanking regulatory sequences of the Mrp3 gene are involved in the activation of Mrp3 in response to these events. The results reported here suggest that MRP3 may participate in wound healing and hair follicle cycle as a growth factor and/or angiogenesis factor.