Recombination Sites within the I Region of the Mouse H-2 Complex

Abstract

Recombinant mouse strains have been important in the development of the genetic map of the H-2 complex and have been used to subdivide the H-2 complex into the K, D, Qa, Tla regions containing genes for class I MHC molecules; I region containing genes for class II MHC molecules; and S region containing genes for class III MHC molecules. A molecular map of the H-2 complex has also been developed with about 1,600 Kb of DNA having been cosmid cloned. The I region has been shown to consist of a 270 Kb segment of DNA that contains six class I genes: A_β2, A_β, A_α, E_β, E_β2 and E_α (Steinmetz et al. 1982). Over the last few years recombinant mouse strains with crossovers in the I region have been analyzed by DNA restriction fragment analysis and DNA sequencing (Steinmetz et al. 1982, 1986, Kobori et al. 1984, 1986, Lafuse et al. 1986, Lafuse and David, 1986, Begovich et al. 1985, Saha and Cullen 1986, Zimmerer et al. 1987). These studies have shown that recombination within the I region is not random but is limited to two specific locations. These sites which have been termed recombination hot spots are located within the E_β and E_α genes. In this report we will review these studies and discuss the implication that there are haplotype specific sequences that promote recombination at these two sites. We will also report studies on additional recombinants mapping within the I region.