By performing a comprehensive degenerate PCR cloning and developmental and tissuespecific expression analysis of Cys2-His2 type zinc finger (ZF) genes expressed in mouse bone marrow HSC population (Lin'Sca-1 cells) we have identified several new ZF genes with differential expression in specific stages of blood cell development. Here we describe Vulcan and Tycho, two new ZF genes with tissue-restricted and developmentally regulated expression during hematopoiesis. Vulcan encodes a ZF protein with a novel type of KRAB A represser domain, which is expressed throughout mouse embryonic development, and in adult thymus, spleen, thyroid, submaxillary gland, brain and testis. During embryonic hematopoiesis Vulcan is expressed both in mouse fetal liver HSC (Sca-lY-fa'r AA4.rLin~ cells) and progenitor cells (AA4.1 ). In adult mice expression of Vulcan is upregulated as mouse bone marrow HSC (LiirSca-1 and Rh-12310"Sca-lY-fa'r Lin-) differentiate into progenitors (Lin Sea-1" cells), and lymphoid (pro-B, pre-B and T cells) and myeloid cell types. Interestingly, Vulcan is not expressed in HPP-CFC progenitors. Tycho gene encodes a 425 aa protein with 11 Cys2-His2 ZF domains, which is expressed throughout mouse embryonic development, and at a very low level in adult mouse brain, liver, heart, and testis. During embryonic hematopoiesis expression of Tycho is upregulated as mouse fetal liver HSC (Sea- l c-fa'r AA4.1 Lin cells) differentiate into progenitors (AA4.1 cells). Compared to mouse bone marrow HSC (Lin Sca-14 and Rh-12311>wSca-lV-tir Lin-) , transcription of Tycho is up-regulated 2-4-fold in progenitors (Lin Sea-1 cells) and pluripotent progenitor cell lines, and 6 to 8-fold in spleen, thymus and T cell lines. HPP-CFC cells, myeloid progenitors, monocytes, macrophages and B lineage cells (pro-B, pre-B, B) do not express or express low levels of Tycho. We are currently studying (a) the expression of Vulcan and Tycho in sorted common lymphoid (CLP) and myeloid (CMP) progenitors, and (b) the effect of over-expression of Vulcan and Tycho on proliferation and differentiation potential of pluripotent progenitor cell line EML Cl. To study the in vivo role of Vulcan and Tycho in HSC/progenitor cell differentiation, we have determined the gene structure and prepared targeting constructs to generate knockout mice.
|Original language||English (US)|
|Issue number||11 PART II|
|State||Published - Dec 1 2000|
ASJC Scopus subject areas
- Cell Biology