Testis-specific Fankl gene in knockdown mice produces oligospermia via apoptosis

Fankl is exclusively expressed in the testis from the meiosis phase to the haploid phase of spermatogenesis. In this study, we examined the function of Fankl by establishing a Fankl-knockdown transgenic mouse model. The apoptotic statuses of the testes of the transgenic mice were tested using the terminal deoxynucleotidyl transferase dUTP nick end labeling （TUNEL） method. The FANK1 consensus DNA-binding sequence was identified using cyclic amplification of sequence target （CAST） analysis. Differentially expressed genes were examined using microarray analysis. A reduction in sperm number and an increase in apoptotic spermatocytes were observed in Fankl-knockdown mice, and the apoptotic cells were found to be primarily spermatogonia and spermatocytes. The CAST results demonstrated that the consensus DNA-binding sequence was AAAAAG, in which the percentage occurrence of each base at each position ranged from 55 to 86%. This sequence was present in the promoter regions of 10 differentially expressed genes that were examined using microarray analysis. In total, 17 genes were differentially expressed with changes in their expression levels greater than twofold. The abnormal expression of Fankl target genes that were regulated directly or indirectly by Fankl reduced the number of sperm in the knockdown mice. Thus, FANK1 may Dlav a pivotal role in sDermato^enesis as a transcription factor.Fankl is exclusively expressed in the testis from the meiosis phase to the haploid phase of spermatogenesis. In this study, we examined the function of Fankl by establishing a Fankl-knockdown transgenic mouse model. The apoptotic statuses of the testes of the transgenic mice were tested using the terminal deoxynucleotidyl transferase dUTP nick end labeling （TUNEL） method. The FANK1 consensus DNA-binding sequence was identified using cyclic amplification of sequence target （CAST） analysis. Differentially expressed genes were examined using microarray analysis, A reduction in sperm number and an increase in apoptotic spermatocytes were observed in Fankl-knockdown mice, and the apoptotic cells were found to be primarily spermatogonia and spermatocytes. The CAST results demonstrated that the consensus DNA-binding sequence was AAAAAG, in which the percentage occurrence of each base at each position ranged from 55 to 86%. This sequence was present in the promoter regions of 10 differentially expressed genes that were examined using microarray analysis. In total, 17 genes were differentially expressed with changes in their expression levels greater than twofold. The abnormal expression of Fankl target genes that were regulated directly or indirectly by Fankl reduced the number of sperm in the knockdown mice. Thus, FANK1 may play a pivotal role in spermatogenesis as a transcription factor.

GST-Fank1融合蛋白表达载体构建及表达纯化的研究

目的研究转录因子Fank1与GST融合蛋白原核表达载体的构建和表达。方法根据Fank1基因的DNA序列,经引物设计软件Primer Premier 5.0优化设计出上下游引物(Ⅰ,Ⅱ),同时在5′端引入BamHⅠ酶切位点,3’端引入SalⅠ酶切位点。以pdsRED-Fank1质粒为模板进行PCR扩增Fank1目的片段,经限制性内切酶酶切后连接到原核表达载体pGEX4T-2,构建成pGEX4T-2-Fank1原核表达载体,转化大肠埃希菌BL21(DE3),通过异丙基硫代-β-D半乳糖苷诱导进行目的蛋白表达。结果经菌液PCR、电泳分析及测序证明成功构建了Fank1融合表达载体,融合蛋白产物经蛋白印迹显示,相对分子量为43 kDa的蛋白条带,与预期一致。结论成功构建了pGEX4T-2-Fank1原核表达载体,并在原核细胞中有表达,为进一步研究转录因子Fank1的功能奠定了基础。

人源Fank1蛋白质FN3结构域多肽的原核表达，纯化及晶体筛选

目的纯化人源Fank1（fibronectin type Ⅲ and ankyrin repeat domain1）蛋白质N端FN3（fibronectin typeⅢ，Ⅲ型纤黏连蛋白）结构域蛋白，用于晶体生长的三维结构分析。方法将FN3结构域基因片段克隆至原核表达载体pGEX-6P-1中，将菌落PCR和测序鉴定正确的重组质粒转化E.coli BL21（DE3）后获得表达菌株。该菌株经IPTG诱导高效表达出带有GST标签的可溶性的融合蛋白，经过Glutathione Sepha-rose^TM 4B亲和层析、Hiload16／60 superdex200分子筛层析纯化后，蛋白纯度达到95％以上。结果纯化蛋白采用悬滴气相扩散法得到棒状晶体。结论成功制备了高纯度FN3蛋白，获得FN3蛋白质晶体，为进一步的三维结构解析及Fank1功能研究奠定了基础。