The Role of Sp1 and Sp3 Transcription Factors in Hematopoiesis

Hematopoiesis is the generation of all mature blood cells from a rare pool of hematopoietic stem cells (HSCs). These blood cells serve a variety of essential functions in the vertebrate body, including gas transport, defense against pathogens, blood clotting and removal of apoptotic cells. Due to their limited life span, they need to be generated continuously throughout life in the stem cell niches of the bone marrow and several discrete anatomical niches that change rapidly, accompanying the highly dynamic processes characteristic of embryonic development. Multi-potent hematopoietic stem cells give rise to a succession of progenitors from which mature blood cells are derived. The hematopoietic system is made up of all mature blood cell types including erythrocytes, platelets, and other cells of the myeloid and lymphoid lineages. Multiple waves of hematopoiesis occur during embryonic development. The initial wave of blood production, termed primitive hematopoiesis, occurs in the mammalian yolk sac followed by definitive hematopoiesis originating from long term-hematopoietic stem cells that arise from the aorta-gonad-mesonephros (AGM) origin

A crucial role for the ubiquitously expressed transcription factor Sp1 at early stages of hematopoietic specification

Mammalian development is regulated by the interplay of tissue-specific and ubiquitously expressed transcription factors, such as Sp1. Sp1 knockout mice die in utero with multiple phenotypic aberrations, but the underlying molecular mechanism of this differentiation failure has been elusive. Here, we have used conditional knockout mice as well as the differentiation of mouse ES cells as a model with which to address this issue. To this end, we examine