Characterization of candidate histone methyltransferases

我们继续对候选组蛋白甲基转移酶Setdb2在人类、小鼠和其他几种哺乳动物组织中的转录进行全面分析，揭示了选择性剪接和嵌合转录物的组织特异性表达。-我们继续鉴定和表征将Setdb2与相邻的独立基因Phf11连接起来的框内和框外融合转录本，Phf11编码含锌指的植物同源结构域基序。-我们使用酵母两个杂交筛选扩展了几种假定的组蛋白甲基转移酶的蛋白质结合伙伴的分析；大多数这些结合伙伴现在已经通过共免疫沉淀实验验证。Setdb2与鉴定的结合伙伴（包括未注释的蛋白和其他生物学上感兴趣的蛋白）之间相互作用的其他功能表征已经进行了。-我们继续描述了缺乏70-80% Setdb2转录本和可能大部分或全部编码蛋白的半胚敲除小鼠模型的部分渗透表型。这些基因敲除在不同小鼠品系背景下的表型表征继续进行。偶有纯合子形小鼠出现早期髓系增生、脾肿大和/或皮炎。-针对小鼠和人Setdb2的特异性抗体已被开发并进一步鉴定。我们在杆状病毒中表达了重组Setdb2，以方便表征其生化活性。-我们扩展了Setdb2是一种非典型组蛋白甲基转移酶的发现，因为它也可以甲基化其他细胞蛋白，包括HIV-1 Tat蛋白。

The Symer lab group: - We continued a comprehensive analysis of transcription of a candidate histone methyltransferase, Setdb2, in human, mouse and several other mammalian organisms tissues, revealing tissue-specific expression of alternatively spliced and chimeric transcripts. - We continued to identify and characterize in-frame and out-of-frame fusion transcripts linking Setdb2 to an adjacent independent gene, Phf11, which encodes a zinc finger-containing plant homeodomain motif. - We extended analysis of several protein-binding partners for the putative histone methyltransferases using yeast two hybrid screens; most of these binding partners now have been validated by co-immunoprecipitation experiments. Additional functional characterization of interactions between Setdb2 and the identified binding partners, which include an unannotated protein and other biologically interesting proteins, has been conducted. - We continued to characterize the partially penetrant phenotypes of a hypomorphic knockout mouse model lacking 70-80% of Setdb2 transcripts and probably most or all encoded proteins. Phenotypic characterization of these knockouts on various mouse strain backgrounds continued. Occasional homozygous hypomorphic mice developed an early myeloid lineage hyperproliferation, enlarged spleens, and/or dermatitis. - Specific antibodies against mouse and human Setdb2 have been developed and further characerized. We have expressed recombinant Setdb2 in baculovirus to facilitate characterization of its biochemical activities. - We extended findings that Setdb2 is an atypical histone methyltransferase, as it may also methylate other cellular proteins including HIV-1 Tat protein.