Joyner A L, Lebo R V, Kan Y W, Tjian R, Cox D R, Martin G R
Nature. 1985;314(6007):173-5. doi: 10.1038/314173a0.
Specific genes are assumed to regulate pattern formation in the mammalian embryo, but as yet none has been identified unequivocally. It is possible that such genes in mammals may be identified by virtue of a conserved coding sequence, because many of the Drosophila melanogaster homoeotic and segmentation genes, which have crucial roles in the regulation of segmental pattern formation during embryonic development, contain a 180-base pair (bp) DNA sequence, the homoeo box, and that sequences homologous to the Drosophila homoeo box are also present in 6-10 copies in higher animals, including mammals. Although the assumption that the homoeo box identifies genes responsible for pattern formation in mammals remains to be validated, it is a particularly attractive hypothesis given the strong conservation of homoeo boxes over vast evolutionary distances. Here we report the localization of a human homoeo box region, previously cloned and shown to contain two homoeo boxes within a sequence of 5-kilobases (kb), to the long arm of chromosome 17. We show that two single-copy homoeo box-flanking probes derived from this region strongly hybridize to single-copy restriction fragments in mouse genomic DNA and that these conserved homoeo box-flanking sequences map to mouse chromosome 11. This may be significant as several genes that map to chromosome 17 in human also map to chromosome 11 in the mouse, implying that a segment of mouse chromosome 11 is homologous to a region of human chromosome 17. Taken together, these data suggest that the homoeo box region detected with our probes is highly conserved in human and mouse.
特定基因被认为调控哺乳动物胚胎的模式形成，但至今尚未明确鉴定出任何一个。哺乳动物中的此类基因有可能凭借保守的编码序列得以鉴定，因为许多在胚胎发育期间调控节段模式形成中起关键作用的黑腹果蝇同源异型基因和分节基因，都包含一个180个碱基对（bp）的DNA序列，即同源异型框，而且在包括哺乳动物在内的高等动物中也存在6 - 10个与果蝇同源异型框同源的序列。尽管同源异型框可鉴定负责哺乳动物模式形成的基因这一假设仍有待验证，但鉴于同源异型框在漫长进化距离上的高度保守性，这是一个特别有吸引力的假说。在此我们报告一个人类同源异型框区域的定位，该区域先前已被克隆并显示在5千碱基（kb）的序列中包含两个同源异型框，定位于17号染色体长臂。我们表明，源自该区域的两个单拷贝同源异型框侧翼探针与小鼠基因组DNA中的单拷贝限制性片段强烈杂交，并且这些保守的同源异型框侧翼序列定位于小鼠11号染色体。这可能具有重要意义，因为一些在人类中定位于17号染色体的基因在小鼠中也定位于11号染色体，这意味着小鼠11号染色体的一段与人类17号染色体的一个区域同源。综合这些数据表明，用我们的探针检测到的同源异型框区域在人类和小鼠中高度保守。
