Karni R J, Wangh L J, Sanchez J A
Department of Biology, Brandeis University, Waltham, MA 02454-0911, USA.
Chromosoma. 2001 Aug;110(4):267-74. doi: 10.1007/s004120100145.
The nuclei of human neutrophils typically consist of a linear array of three or four lobes joined by DNA-containing filaments. Terminal lobes are connected to internal lobes via a single filament, while internal lobes have two filaments, each to an adjacent lobe. Some lobes also have appendages of various shapes and sizes. In particular, up to 17% of neutrophil nuclei of healthy women exhibit a drumstick-shaped appendage that contains the inactive X chromosome. This report provides a detailed analysis of the relationship between nuclear morphology and the location of the X and Y chromosomes in human neutrophils. Fluorescent in situ hybridization analysis revealed that the X and the Y chromosomes of male neutrophil nuclei are randomly distributed among nuclear lobes. Similarly, in female neutrophil nuclei with a drumstick appendage, the active X chromosome is also randomly distributed among lobes. In contrast, the inactive X chromosome is preferentially located in a terminal lobe in over 90% nuclei with drumsticks. Within the terminal lobe of nuclei with drumsticks, the inactive X chromosome lies distal to the point of filament attachment in 80% of the nuclei. The inactive X chromosome also exhibits a specific orientation within the drumstick appendage, with over 95% of nuclei having the X centromere located toward the tip of the appendage. Female nuclei without a drumstick appendage also have one of the X chromosomes (presumably the inactive chromosome) preferentially situated in a terminal lobe. Nonrandom distribution of the inactive X chromosome is discussed in the context of a model that considers chromosomes as determinants of neutrophil nuclear morphology.
人类中性粒细胞的细胞核通常由三或四个叶组成线性排列，这些叶由含DNA的细丝连接。末端叶通过单根细丝与内部叶相连，而内部叶有两根细丝，每根细丝连接到相邻的叶。一些叶还具有各种形状和大小的附属物。特别是，健康女性高达17%的中性粒细胞核呈现出含有失活X染色体的鼓槌状附属物。本报告详细分析了人类中性粒细胞核形态与X和Y染色体位置之间的关系。荧光原位杂交分析显示，男性中性粒细胞核中的X和Y染色体随机分布在核叶之间。同样，在具有鼓槌状附属物的女性中性粒细胞核中，活跃的X染色体也随机分布在叶之间。相比之下，在超过90%有鼓槌的核中，失活的X染色体优先位于末端叶。在有鼓槌的核的末端叶内，80%的核中失活的X染色体位于细丝附着点的远端。失活的X染色体在鼓槌状附属物内也呈现出特定的方向，超过95%的核中X着丝粒朝向附属物的尖端。没有鼓槌状附属物的女性核中也有一条X染色体（可能是失活染色体）优先位于末端叶。在将染色体视为中性粒细胞核形态决定因素的模型背景下，讨论了失活X染色体的非随机分布。
