Shiroishi T, Hanzawa N, Sagai T, Ishiura M, Gojobori T, Steinmetz M, Moriwaki K
Department of Cell Genetics, National Institute of Genetics, Mishima, Japan.
Immunogenetics. 1990;31(2):79-88. doi: 10.1007/BF00661217.
The wm7 haplotype of the major histocompatibility complex (MHC), derived from the Japanese wild mouse Mus musculus molossinus, enhances recombination specific to female meiosis in the K/A beta interval of the MHC. We have mapped crossover points of fifteen independent recombinants from genetic crosses of the wm7 and laboratory haplotypes. Most of them were confined to a short segment of approximately 1 kilobase (kb) of DNA between the A beta 3 and A beta 2 genes, indicating the presence of a female-specific recombinational hotspot. Its location overlaps with a sex-independent hotspot previously identified in the Mus musculus castaneus CAS3 haplotype. We have cloned and sequenced DNA fragments surrounding the hotspot from the wm7 haplotype and the corresponding regions from the hotspot-negative B10.A and C57BL/10 strains. There is no significant difference between the sequences of these three strains, or between these and the published sequences of the CAS3 and C57BL/6 strains. However, a comparison of this A beta 3/A beta 2 hotspot with a previously characterized hotspot in the E beta gene revealed that they have a very similar molecular organization. Each hotspot consists of two elements, the consensus sequence of the mouse middle repetitive MT family and the tetrameric repeated sequences, which are separated by 1 kb of DNA.
主要组织相容性复合体（MHC）的wm7单倍型源自日本野生小鼠小家鼠，可增强MHC的K/Aβ区间内雌性减数分裂特有的重组。我们已绘制了来自wm7和实验室单倍型遗传杂交的15个独立重组体的交叉点。其中大多数局限于Aβ3和Aβ2基因之间约1千碱基（kb）的短DNA片段，表明存在雌性特异性重组热点。其位置与先前在小家鼠栗色CAS3单倍型中鉴定的性别独立热点重叠。我们已从wm7单倍型克隆并测序了热点周围的DNA片段，以及来自热点阴性的B10.A和C57BL/10品系的相应区域。这三个品系的序列之间，以及它们与已发表的CAS3和C57BL/6品系的序列之间均无显著差异。然而，将这个Aβ3/Aβ2热点与Eβ基因中先前表征的热点进行比较发现，它们具有非常相似的分子组织。每个热点由两个元件组成，即小鼠中间重复MT家族的共有序列和四聚体重复序列，它们被1 kb的DNA隔开。
