Further contributions to the genetic aspect of congenital sensorineural deafness in Dalmatians

Sensorineural deafness is a common congenital disorder in Dalmatians and is genetically transmitted. Different modes of inheritance have been proposed and the objective of this study was to study these by segregation analyses using maximum likelihood procedures. Data from 33 complete Dalmatian families were collected and data from 56 single Dalmatians added. This resulted in a total of 575 dogs with 357 known phenotypes. All dogs were clinically evaluated and electrophysiologically tested with brainstem auditory evoked responses.The prevalence of deafness was 16.5% (9.4% unilaterally deaf, 7.1% bilaterally deaf). Females were 4.4% more affected than males but this difference was not significant. Within the same litter, different phenotypic expressions of deafness occurred, which suggested different expressions of the disease. In addition, two data sets were analysed: the first included normal, uni- and bilaterally deaf dogs, the second had normal and deaf Dalmatians. We found that a recessive allele at a single biallelic major locus fitted our data best, although an incomplete penetrance of the recessive homozygotes was observed.     

在羊驼皮肤黑色素细胞中α-黑素细胞刺激素对诱导一氧化氮合酶的影响

为研究α-黑素细胞刺激素（α-Melanocytestimulatinghormone,α-MSH）对诱导型一氧化氮合酶（NOS2）在羊驼皮肤黑素细胞中的影响。采用体外培养正常羊驼皮肤黑素细胞,检测不同浓度α-MSH（0、10-9、10^-8、10^-7moL／L）对羊驼皮肤黑素细胞中诱导型一氧化氮合酶（NOS2）基因...     

miR-186-5p与α-MSH互作对绵羊黑素细胞黑色素生成的影响

黑色素合成受多种基因和miRNAs的调控,为了研究miR-186-5p与α-MSH协同作用对绵羊黑素细胞黑色素生成的影响.本研究在绵羊黑素细胞中转染miR-186-5p表达载体,同时添加α-MSH,通过实时荧光PCR(quantitative real time polymerase chain reaction,qR...     

小鼠Oct-1基因CDS区克隆与生物信息学分析

为研究小鼠Oct-1基因的生物学特性,试验扩增小鼠黑色素细胞中Oct-1基因CDS区序列,并运用生物信息学软件分析小鼠Oct-1基因序列的特性、编码蛋白理化性质、亚细胞定位、靶基因及保守性结构域等,从而预测其是否调控黑色素的生成。结果表明,小鼠Oct-1基因大小为2 313 bp,编码蛋白质的分子式C₃₄₂₅H₅₆₀₆N₉₇₆O₁₁₆₃S₁₅,是一个不稳定可溶性蛋白质,二级结构以无规卷曲和α-螺旋为主,亚细胞定位主要分布在细胞核,推测其可能在能量代谢和辅因子的生物合成过程中发挥信号转导和转录因子调控的作用;Oct-1基因在小鼠黑色素细胞中表达,其编码的蛋白含有一个保守的POU结构域和一个保守的同源域,参与调控13个黑色素形成相关基因转录表达,在黑色素生成关键基因MITF、TYR、TYRP1、TYRP2的启动子上存在Oct-1转录因子的作用位点,Oct-1蛋白质还可能与Brf2、Pou2af1、Tbp等蛋白相互作用调控毛色基因表达,故可以推测转录因子Oct-1在黑素细胞的黑色素生成中发挥着重要的作用,为研究毛色形成机制提理论依据。     

Melanocytogenesis and melanogenesis: genetic regulation and comparative clinical diseases

Murine models recently provided important information on the pathogenesis of pigmentation disorders. Multiple factors influence melanocyte function at various levels, such as melanoblast development and migration from the neural crest to peripheral sites, melanoblast differentiation into melanocytes, melanocyte survival and, finally, synthesis of melanosomes and melanins. Mutations affecting any of these steps result in hereditary hypomelanoses. In some of these diseases, melanocytes are absent, either because of a defect in migration of melanoblasts from the neural crest, their inability to survive and/or proliferate in colonized territories (piebaldism and Waardenburg syndromes), or because of programmed melanocyte destruction (e.g. vitiligo). In other entities, the melanocytes are present but functionally deficient (oculocutaneous albinisms and pigmentary dilutions). This comprehensive review will introduce the genetic regulation of melanocytogenesis and melanogenesis and the correlations between genetic abnormalities and hypopigmentation clinical disorders.     

羊驼毛色相关基因研究进展的综述

羊驼毛纤维颜色丰富,具有22种天然色,与其他哺乳动物一样,主要由遗传基因决定。掌握控制羊驼毛色基因的改变,可以有效地控制羊驼毛色的转变。哺乳动物的毛色表型与动物体内黑色素的种类、数量、合成及分布有关。在羊驼皮肤组织中,Agouti基因、MC1R基因、酪氨酸酶基因家族、KIT基因、AIF基因、β-catenin基因、Wnt3α基因、Mitf-M基因、EDNRA基因、EDNRB基因、CDK5基因、PRS5基因、P基因及花斑突变都参与羊驼毛色的形成与调控。综述了羊驼毛色相关基因的研究进展。     

动物黑色素细胞及其相关性状形成机制的研究进展

黑色素细胞是合成黑色素的细胞，由其前体细胞黑色素母细胞分化而来，胚胎期黑色素母细胞的形成有两次，一次是具有黑色素细胞特性的神经嵴细胞沿背外侧迁移而形成，另一次是由沿腹侧迁移的神经嵴细胞亚细胞雪旺氏细胞前体（Schwann cell precursors，SCPs）受到某种信号诱导后形成，这是皮肤中黑色素细胞形成的主要方式。黑色素细胞的形成与动物毛发颜色及其他重要经济性状密切相关，其形成的增多或减少，异位形成或异位侵袭均可能导致相应的疾病，但脊椎动物中具有典型黑色素细胞异位形成特征的乌骨鸡却繁衍至今，而且是重要的食用和药用经济动物。探索黑色素细胞的形成及其对相关性状的影响不但能为动物经济性状育种提供相关理论基础，也可为相关疾病的治疗提供理论依据。作者从黑色素细胞的来源及其形成过程中参与的信号因子来探讨其形成机制，并对黑色素细胞相关性状的形成机制尤其是乌质性状进行综述。     

Anti-melanogenic effects of black,green, and white tea extracts on immortalized melanocytes

Tea contains polyphenols and is one of the most popular beverages consumed worldwide. Because most tyrosinase inhibitors that regulate melanogenesis are phenol/catechol derivatives, this study investigated the inhibitory effects of Camellia sinensis water extracts (CSWEs), including black tea, green tea, and white tea extracts, on melanogenesis using immortalized melanocytes. CSWEs inhibited melanin accumulation and melanin synthesis along with tyrosinase activity in a concentration-dependent manner. These inhibitory effects were superior to those of arbutin, a well-known depigmenting agent. The anti-melanogenic activity of black (fermented) tea was higher than that of a predominant tea catecholamine, epigallocatechin gallate. CSWEs, especially black tea extract, decreased tyrosinase protein levels in a concentration-dependent manner. These results suggest that the anti-melanogenic effect of CSWEs is mediated by a decrease in both tyrosinase activity and protein expression, and may be augmented by fermentation. Thus, CSWEs could be useful skin-whitening agents in the cosmetic industry.