Analysis of transposable elements and organellar DNA in male and female genomes of a species with a huge Y chromosome reveals distinct Y centromeres
Analysis of transposable elements and organellar DNA in male and female genomes of a species with a huge Y chromosome reveals distinct Y centromeres
复制标题
DOI：
10.1111/tpj.13254
复制
发表时间：
2016-11-01
期刊：
影响因子：
7.2
通讯作者：
Renner, Susanne S.
中科院分区：
文献类型：
--
作者：
Sousa, Aretuza;Bellot, Sidonie;Renner, Susanne S.
少数被子植物有明显的Y染色体。其中有宽叶蝇子草（菊科），酸模（桑科）和大瓢虫（葫芦科），后者具有总基因组的10%的雄性/雌性差异（雌性个体具有0.85pg基因组，雄性个体0.94pg），这是由于大约300万年前出现的Y染色体。利用21种重复DNA（包括16个移动的元件）开发的探针，比较了巨桉雌雄株的序列组成，并测定了重复DNA和细胞器DNA在染色体上的分布。Y染色体的大小很大程度上是由于某些重复序列的积累，例如Ty 1/copia和Ty 3/gypsy超家族的成员，一个未分类的元件和一个卫星，还有质体和质体衍生的序列。在X染色体和常染色体的着丝粒上有一个144 bp的丰富的串联重复序列，但在Y染色体的着丝粒上没有。免疫组化染色与pericentromere特异性标记抗组蛋白H3 Ser 10 ph和H2 AThr 120 ph揭示了这些组蛋白标记的Y-特异性延伸。Y着丝粒与其他所有着丝粒的组成不同，这引起了关于其纺锤体附着的问题，并表明着丝粒或近着丝粒染色质可能参与了重组的抑制。
Few angiosperms have distinct Y chromosomes. Among those that do are Silene latifolia (Caryophyllaceae), Rumex acetosa (Polygonaceae) and Coccinia grandis (Cucurbitaceae), the latter having a male/female difference of 10% of the total genome (female individuals have a 0.85pg genome, male individuals 0.94pg), due to a Y chromosome that arose about 3 million years ago. We compared the sequence composition of male and female C.grandis plants and determined the chromosomal distribution of repetitive and organellar DNA with probes developed from 21 types of repetitive DNA, including 16 mobile elements. The size of the Y chromosome is largely due to the accumulation of certain repeats, such as members of the Ty1/copia and Ty3/gypsy superfamilies, an unclassified element and a satellite, but also plastome- and chondriome-derived sequences. An abundant tandem repeat with a unit size of 144bp stains the centromeres of the X chromosome and the autosomes, but is absent from the Y centromere. Immunostaining with pericentromere-specific markers for anti-histone H3Ser10ph and H2AThr120ph revealed a Y-specific extension of these histone marks. That the Y centromere has a different make-up from all the remaining centromeres raises questions about its spindle attachment, and suggests that centromeric or pericentromeric chromatin might be involved in the suppression of recombination.