Mice mutant in the DM domain gene Dmrt4 are viable and fertile but have polyovular follicles

Proteins containing the DM domain, a zinc finger-like DNA binding motif, have been implicated in sexual differentiation in diverse metazoan organisms. Of seven mammalian DM domain genes, only Dmrt1 and Dmrt2 have been functionally analyzed. Here, we report expression analysis and targeted disruption of Dmrt4 (also called DmrtA1) in the mouse. Dmrt4 is widely expressed during embryonic and postnatal development. However, we find that mice homozygous for a putative null mutation in Dmrt4 develop essentially normally, undergo full sexual differentiation in both sexes, and are fertile. We observed two potential mutant phenotypes in Dmrt4 mutant mice. First, ovaries of most mutant females have polyovular follicles, suggesting a role in folliculogenesis. Second, 25% of mutant males consistently exhibited copulatory behavior toward other males. We also tested potential redundancy between Dmrt4 and two other gonadally expressed DM domain genes, Dmrt1 and Dmrt7. We observed no enhancement of gonadal phenotypes in the double mutants, suggesting that these genes function independently in gonadal development.     

大熊猫Dmrt基因家族4个成员基因的克隆

果蝇Doublesex基因、线虫Mab-3基因和人类DMRTI基因均含有一个新的具有DNA结合能力的保守基序,即DM结构域。它们在性别决定和分化发育的调控过程中具有相似的功能。通过简并PCR克隆技术,扩增和克隆了大熊猫基因组中的DM结构域,得到了4个具有不同DM序列的克隆。结果显示,在大熊猫基因组中存在Dmrt基因家族的多个成员。该基因家族在脊椎动物和非脊椎动物都具有高度的进化保守性。     

Expression of Dmrt1 in the genital ridge of mouse and chicken embryos suggests a role in vertebrate sexual development.

Sex-determining mechanisms are highly variable between phyla. Only one example has been found in which structurally and functionally related genes control sex determination in different phyla: the sexual regulators mab-3 of Caenorhabditis elegans and doublesex of Drosophila both encode proteins containing the DM domain, a novel DNA-binding motif. These two genes control similar aspects of sexual development, and the male isoform of DSX can substitute for MAB-3 in vivo, suggesting that the two proteins are functionally related. DM domain proteins may also play a role in sexual development of vertebrates. A human gene encoding a DM domain protein, DMRT1, is expressed only in the testis in adults and maps to distal 9p24.3, a short interval that is required for testis development. Earlier in development we find that murine Dmrt1 mRNA is expressed exclusively in the genital ridge of early XX and XY embryos. Thus Dmrt1 and Sry are the only regulatory genes known to be expressed exclusively in the mammalian genital ridge prior to sexual differentiation. Expression becomes XY-specific and restricted to the seminiferous tubules of the testis as gonadogenesis proceeds, and both Sertoli cells and germ cells express Dmrt1. Dmrt1 may also play a role in avian sexual development. In birds the heterogametic sex is female (ZW), and the homogametic sex is male (ZZ). Dmrt1 is Z-linked in the chicken. We find that chicken Dmrt1 is expressed in the genital ridge and Wolffian duct prior to sexual differentiation and is expressed at higher levels in ZZ than in ZW embryos. Based on sequence, map position, and expression patterns, we suggest that Dmrt1 is likely to play a role in vertebrate sexual development and therefore that DM domain genes may play a role in sexual development in a wide range of phyla.     

大头蛙4个Dmrt基因DM保守区的序列分析

Dm rt基因家族是新近发现的一个与性别决定相关的基因家族。该家族成员编码的蛋白质都含有一个具有DNA结合能力的保守基序?DM结构域,在性别决定和分化发育的调控中担负重要的功能。采用简并PCR技术扩增了大头蛙Dm rt基因的DM结构域,经序列分析,获得了Dm rt基因家族的4个成员LfDm rt1a,LfDm-rt1b,LfDm rt3,LfDm rt5。与其它动物相关的Dm rt基因进行氨基酸序列聚类分析,结果表明,不同进化地位动物的Dm rt基因DM域编码序列存在高度的同源性,显示Dm rt基因在系统进化上高度保守,序列上的相似性可能暗示它们在功能上的保守性。     

赤子爱胜蚓5个Dmrt基因的序列分析

本文采用简并PCR技术,扩增了赤子爱胜蚓Dmrt基因的DM结构域,经序列分析,获得了Dmrt基因家族的5个成员EfDmrt2、EfDmrt3、EfDmrt4a、EfDmrt4b、EfDmrt4c.与其他动物相关的Dmrt基因进行聚类分析,结果表明,不同进化地位动物的Dmrt基因DM域编码序列存在高度的同源性,显示Dmrt基因在系统进化上高度保守,序列上的相似性可能暗示它们在功能上的保守性.     

黄鳝性腺高表达的核糖体蛋白基因

采用高密点阵技术从黄鳝雄性性腺cDNA文库中获得8个克隆,序列分析和BLAST结果显示它们编码的蛋白质分别与40S核糖体蛋白S4,S9,S16,S17,S20和60S核糖体蛋白L7, L18a,L29高度同源。 根据黄鳝RP蛋白序列和其他物种的相应同源序列构建ML系统发生树,显示核糖体蛋白基因在进化中高度保守。核糖体蛋白基因不仅可作为分子进化分析的有利工具,而且从它们的表达模式显示RP基因除具有看家基因的功能外,很有可能参与包括性腺分化等过程的发育调控。Abstract: 8 cDNA clones have been isolated from a cDNA library prepared from swamp eel testies by macroarray. DNA sequence analysis and database search showed that they encode 8 proteins which are highly homologous to 40S ribosomal proteins S4,S9,S16,S17,S20 and 60S riobosomal proteins L7, L18a,L29. Phylogenetic trees (ML) based on ribosomal protein genes from swamp eel and other organisms has been reconstructed, which showed that ribosomal protein genes were highly conserved during evolution. These results suggested that ribosomal protein genes as house keeping genes may play roles in developmental regulation such as sexual differentiation and can also be used as markers for the study of molecular evolution.     

中华绒螯蟹Dmrt基因保守区段的克隆和序列分析

Dmrt基因家族是一个与性别决定和发育相关的基因家族,在不同进化类型的生物中具有相当的保守性。采用PCR技术,扩增了中华绒螯蟹Dmrt基因的DM结构域。经序列分析,获得了Dmrt基因家族的4个成员基因EsDmrt2a、EsDmrt2b、EsDmrt2c和EsDmrt5。结果表明,不同进化地位动物的Dmrt2和Dmrt2基因DM域编码序列存在高度的同源性,显示Dmrt基因在系统进化上高度保守,序列上的相似性可能暗示着它们在功能上的保守性。     

Mice deficient in Dmrt7 show infertility with spermatogenic arrest at pachytene stage

Genes including DM domain regulate sexual development in diverse metazoan phyla. One of these genes, Dmrt7, was expressed only in testes of adult mice. To determine the role of Dmrt7 in mice, we generated Dmrt7-knockout mice (Dmrt7-/-). Although the Dmrt7-/- showed normal growth, null males were infertile. No sperm was detected in the epididymis of Dmrt7-/- adult males. Absence of spermatids in a histological analysis, decreased expression of Ccna1 mRNA and the accumulation of SCP3-positive spermatocytes showed the arrest of spermatogenesis at the pachytene stage in the Dmrt7-knockout mice.     

山地麻蜥7个Dmrt基因成员的克隆及序列分析

Dm rt基因家族是一个与性别决定相关的基因家族。该家族成员都含有一个具有DNA结合能力的保守基序———DM结构域,在性别决定和分化发育的调控中担负着重要的功能。本文采用简并PCR技术,扩增和克隆了山地麻蜥(Erem ias breuchleyi)基因组中的DM结构域,通过SSCP技术筛选和测序得到了7个具有不同DM序列的克隆。结果显示,在山地麻蜥基因组中存在着Dm rt基因家族的多个成员,与其他动物相关的Dm rt基因进行聚类分析,显示该基因家族在动物系统进化上具有高度的保守性。