Human IgH locus

Bruggemann M, Spicer C, Buluwela L, Rose-well 1, Barton S, Surani MA, Babbitts TH. 1991. Human antibody production in transgenic mice expression from 100 kb of the human IgH locus. Eur J Immunol 21, 1323-1326. 

The human A locus is located on chromosome 22. As in the case of the human Igh locus, the A genes were first tentatively mapped by studies measuring immunoglobulin gene expression in somatic cell hybrids [91] and the chromosome assignment later confirmed by direct hybridization studies [99]. 

Fig. 1. IgH locus of human and mouse. Constant region genes are indicated by closed boxes, switch regions by stippled boxes. The switch regions 5 of human al, e. and a2 are not precisely localized. In addition JH segments (vertical line with shorter lines for i/d), the D-Q52 segment ( ]) and areas that have not been overlapped (//) are indicated [11,95,96.31,32,34.35,40] (see also text).

Enhancers are classically defined as DNA sequences which stimulate transcription of a linked gene from its authentic start site. This stimulation is observed with the enhancer placed upstream or downstream of the gene, at a distance of several thousand base pairs and in an orientation-independent manner (for a review see [80]). Enhancers were originally described in viruses but have since been identified in a number of cellular genes. The first cellular enhancer to be found was in the major intron of the mouse heavy chain locus [81-83] and subsequently in the mouse k [84,85] and human IgH loci [86]. 

Fig. 2.5 Structure of the human germ line (a), and rearranged (b) and targeted (c) IgH I locus of the G-line. The targeting vector used in homologous recombination contains the leptin-Fc reporter gene (hobFc) and the blasticidin deaminase...

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