Igh^em1Rcas

CRISPR/cas9 genome editing is used to delete the mouse CH1 (constant heavy chain) exons and replace the mouse VH (variable heavy chain) portion of Igh with a VHH minigene containing: mouse Vh promoter (containing octamer and TATA box, 250 bps), mouse leader exons-intron (150 bp), camelid VHH open reading frame (300 bps), and mouse downstream sequences containing recombination sequences (100 bps). The 15 kD VHH (Variable Heavy chain domains of a Heavy chain or nanobodies [Nbs]) minigene contains 18 alpaca, 7 dromedary and 5 bactrian camel VHH genes in a 25 kB insertion. Each gene is fused to a VH promoter, leader exons and recombination signal sequences. (J:307753)