The Csf1r-EGFP transgenic mouse line was generated by conventional pronuclear injection using a 7.2kb fragment of the mouse Csf1r locus (3.5kb promoter and the first intron, with the Csf1r start codon in exon 1 mutated) placed upstream of the EGFP coding sequence. Recent analysis suggests that there are around 20 copies of the transgene inserted in tandem of mouse chromosome 16. The original transgenic line has been backcrossed extensively to the C57BL/6 background and deposited at the Jackson Laboratories. Csf1r-EGFP mice (MacGreen) have been used extensively in studies of macrophage biology and the active promoter element was also to generate Csf1r-cre, Csf1r-mApple and other transgenes in multiple species. The transgene is expressed in the earliest detectable macrophage-lineage cells in the embryo. In adults, EGFP is also expressed by granulocytes, which express Csf1r mRNA but do not express CSF1R protein.

A macrophage colony-stimulating factor receptor-green fluorescent protein transgene is expressed throughout the mononuclear phagocyte system of the mouse.
Sasmono RT, Oceandy D, Pollard JW, Tong W, Pavli P, Wainwright BJ, Ostrowski MC, Himes SR, Hume DA.Blood. 2003 Feb 1;101(3):1155-63. doi: 10.1182/blood-2002-02-0569. Epub 2002 Sep 12.PMID: 12393599

The colony-stimulating factor 1 receptor is expressed on dendritic cells during differentiation and regulates their expansion.MacDonald KP, Rowe V, Bofinger HM, Thomas R, Sasmono T, Hume DA, Hill GR.J Immunol. 2005 Aug 1;175(3):1399-405. doi: 10.4049/jimmunol.175.3.1399.PMID: 16034075 

Mouse neutrophilic granulocytes express mRNA encoding the macrophage colony-stimulating factor receptor (CSF-1R) as well as many other macrophage-specific transcripts and can transdifferentiate into macrophages in vitro in response to CSF-1.Sasmono RT, Ehrnsperger A, Cronau SL, Ravasi T, Kandane R, Hickey MJ, Cook AD, Himes SR, Hamilton JA, Hume DA.J Leukoc Biol. 2007 Jul;82(1):111-23. doi: 10.1189/jlb.1206713. Epub 2007 Apr 16.PMID: 17438263

Characterisation and trophic functions of murine embryonic macrophages based upon the use of a Csf1r-EGFP transgene reporter.Rae F, Woods K, Sasmono T, Campanale N, Taylor D, Ovchinnikov DA, Grimmond SM, Hume DA, Ricardo SD, Little MH.Dev Biol. 2007 Aug 1;308(1):232-46. doi: 10.1016/j.ydbio.2007.05.027. Epub 2007 May 25.PMID: 17597598

Images below show more recent applications of this transgene in various studies from our research group

microglial cells in the cerebral cortex
Macrophages surrounding the base of the crypts in the small intestine
Csf1r-mApple and Csf1r-EGFP . Macrophages infilitrate interdigital area of footpad in emrbyo around 10.5dpc
An enface view of a Peyer's patch in the mouse ileum, highlights macrophages underlying the dome and the extensive populations in thelamina propria villi