An EGFP gene with poly(A) signal sequence was inserted between the 2nd and 3rd nucleotide of exon 2 of the Il11 gene on BAC clone RP23-285B12 to create an Il11 promoter-driven Il11/EGFP fusion gene coding for the first three Il11 amino-acids followed by the EGFP peptide. The modified BAC was injected into oocytes together with sperm through Intracytoplasmic sperm injection (ICSI). (J:306086)