Montavon Thomas, Soshnikova Natalia
Department of Epigenetics, Max-Planck Institute of Immunobiology and Epigenetics, Stübeweg 51, 79108 Freiburg, Germany.
Institute of Molecular Biology gGmbH (IMB), Ackermannweg 4, 55128 Mainz, Germany.
Semin Cell Dev Biol. 2014 Oct;34:76-84. doi: 10.1016/j.semcdb.2014.06.005. Epub 2014 Jun 12.
Hox genes are critical regulators of embryonic development in bilaterian animals. They exhibit a unique mode of transcriptional regulation where the position of the genes along the chromosome corresponds to the time and place of their expression during development. The sequential temporal activation of these genes in the primitive streak helps determining their subsequent pattern of expression along the anterior-posterior axis of the embryo, yet the precise correspondence between these two collinear processes is not fully understood. In addition, vertebrate Hox genes evolved similar modes of regulation along secondary body axes, such as the developing limbs. We review the current understanding of the mechanisms operating during activation, maintenance and silencing of Hox gene expression in these various contexts, and discuss the evolutionary significance of their genomic organization.
Hox基因是两侧对称动物胚胎发育的关键调节因子。它们呈现出一种独特的转录调控模式，即基因在染色体上的位置与其在发育过程中表达的时间和位置相对应。这些基因在原条中的顺序性时间激活有助于确定它们随后沿胚胎前后轴的表达模式，但这两个共线性过程之间的确切对应关系尚未完全理解。此外，脊椎动物的Hox基因在次生体轴（如发育中的肢体）上也进化出了类似的调控模式。我们综述了目前对这些不同背景下Hox基因表达激活、维持和沉默过程中所涉及机制的理解，并讨论了其基因组组织的进化意义。
