标签： ProSpec CYT-644

CDF, HILDA, D-FACTOR, Differentiation- stimulating factor, Melanoma-derived LPL inhibitor, MLPLI, Emfilermin, Leukemia inhibitory factor, LIF, DIA.

Leukemia Inhibitory Factor also called LIF is a lymphoid factor that promotes long-term maintenance of embryonic stem cells by suppressing spontaneous differentiation. Leukemia Inhibitory Factor has several functions such as cholinergic neuron differentiation, control of stem cell pluripotency, bone & fat metabolism, mitogenesis of factor dependent cell lines & promotion of megakaryocyte production in vivo. Human and mouse LIF exhibit a 78% identity in its amino acid sequence.

白血病抑制因子也称为 LIF，是一种淋巴因子，通过抑制自发分化来促进胚胎干细胞的长期维持。 白血病抑制因子具有多种功能，例如胆碱能神经元分化、干细胞多能性控制、骨和脂肪代谢、因子依赖性细胞系的有丝分裂和促进体内巨核细胞生成。 人和小鼠 LIF 在其氨基酸序列中表现出 78% 的同一性。

Leukemia Inhibitory Factor Human Recombinant produced in E.Coli is a single, non-glycosylated, polypeptide chain containing 180 amino acids and having a molecular mass of 19.7kDa.
The Leukemia Inhibitory Factor is purified by proprietary chromatographic techniques.

在大肠杆菌中产生的白血病抑制因子人重组体是一种单一的、非糖基化的多肽链，含有 180 个氨基酸，分子量为 19.7kDa。
白血病抑制因子通过专有的色谱技术进行纯化。

Escherichia Coli.

Sterile Filtered White lyophilized powder.

Leukemia Inhibitory Factor was lyophilized from a concentrated sterile solution containing 1xPBS pH 7.4.

It is recommended to reconstitute the lyophilized Leukemia Inhibitory Factor in sterile water not less than 100µg/ml, which can then be further diluted to other aqueous solutions.

建议将冻干的白血病抑制因子在不低于 100μg/ml 的无菌水中复溶，然后可以进一步稀释成其他水溶液。

Lyophilized Leukemia Inhibitory Factor although stable at room temperature for 3 weeks, should be stored desiccated below -18°C. Upon reconstitution Leukemia Inhibitory Factor should be stored at 4°C between 2-7 days and for future use below -18°C.
For long term storage it is recommended to add a carrier protein .
Please prevent freeze-thaw cycles.

冻干的白血病抑制因子虽然在室温下可稳定保存 3 周，但应在 -18°C 以下干燥储存。 重构后，白血病抑制因子应在 4°C 下储存 2-7 天，以备将来在 -18°C 以下使用。
对于长期储存，建议添加载体蛋白。
请防止冻融循环。

Greater than 98.0% as determined by:
Analysis by RP-HPLC.
Analysis by -PAGE.

SPLPITPVNA TCAIRHPCHN NLMNQIRSQL AQLNGSANAL FILYYTAQGE PFPNNLDKLC GPNVTDFPPF HANGTEKAKL VELYRIVVYL GTSLGNITRD QKILNPSALS LHSKLNATAD ILRGLLSNVL CRLCSKYHVG HVDVTYGPDT SGKDVFQKKK LGCQLLGKYK QIIAVLAQAF.

The ED50 was determined by the M1 cell differentiation assay is < 0.01 ng/ml, corresponding to a specific activity of 100,000,000IU/mg.

ProSpec’s products are furnished for LABORATORY RESEARCH USE ONLY. The product may not be used as drugs, agricultural or pesticidal products, food additives or household chemicals.

A cytokine that is part of the interleukin 6 family, Leukaemia inhibitory factor or LIF operates in the hypothalamus. Studies have shown that it may play a crucial role in energy homeostasis. The cytokine has also been found in the anterior pituitary and is able to trigger ACTH secretion in vitro and vivo, shown in studies on both mice and men. Indeed, studies have shown low plasma ACTH and damage HPA responses to immune stimuli or stress can both be corrected by LIF administration.

属于白细胞介素 6 家族、白血病抑制因子或 LIF 的细胞因子在下丘脑中起作用。 研究表明，它可能在能量稳态中发挥关键作用。 在对小鼠和男性的研究中也发现了这种细胞因子在垂体前叶中并能够在体外和体内触发 ACTH 分泌。 事实上，研究表明低血浆 ACTH 和损伤 HPA 对免疫刺激或压力的反应都可以通过 LIF 给药来纠正。

Function
LIF gets its name from its power to induce terminal differentiation of myeloid leukemia cells. What this means is that LIF prevents their growth from continuing. You will also find certain other factors attributed to LIF such as influence on bone metabolism, embryogenesis, inflammation, and the growth promotion, as well as the differentiation of different groups of target cells. It is believed by some that LIF could help to improve the implantation rate in women who have experienced unexplained infertility.
LIF has also been shown and indeed suggested as a possible alternate solution to feed cell culture. This is due to the limit that feeder cells actually only create LIF on the surface of the cells. Feeder cells that do not produce the LIF gene have been found not to effectively support stem cells. In contrast, LIF can effectively ensure self renewal. It is able to do this by gaining the activator of Stat3 and the signal transducer. Typically, LIF will be added to stem cell culture with the aim of reducing the chances of spontaneous differentiation.

LIF 得名于其诱导髓性白血病细胞终末分化的能力。这意味着 LIF 阻止了它们的继续增长。您还会发现某些其他归因于 LIF 的因素，例如对骨代谢、胚胎发生、炎症和促生长的影响，以及不同靶细胞群的分化。一些人认为，LIF 有助于提高经历过不明原因不孕症的女性的着床率。
LIF 也已被证明并确实被建议作为补料细胞培养的一种可能的替代解决方案。这是由于饲养细胞实际上只在细胞表面产生 LIF 的限制。已发现不产生 LIF 基因的饲养细胞不能有效地支持干细胞。相比之下，LIF可以有效地保证自我更新。它可以通过获得 Stat3 的激活器和信号传感器来做到这一点。通常，LIF 将被添加到干细胞培养物中，目的是减少自发分化的机会。

 

Structure
The structure of LIF is made of main chain fold that conforms to the four a-helix bundle topology. This has been seen in various other members of the hematopoietic cytokine family. LIF is quite similar in terms of structure to both GH and granulocyte colony-stimulating factor. Studies and x-rays have also shown evidence for regions of conserved surface character.

LIF的结构是由符合四个a-螺旋束拓扑的主链折叠构成的。 这已在造血细胞因子家族的各种其他成员中看到。 LIF 在结构上与 GH 和粒细胞集落刺激因子非常相似。 研究和 X 射线也显示了保守表面特征区域的证据。

 

Interactions
Over the years, studies have shown that LIF interacts with various other factors including the ciliary neurotrophic factor. The two share various common components through their multimeric receptors. The two cytokine receptors both contain gp190/low affinity LIF receptor and gp130/interleukin-60receptor transducer. Research has shown a mutual displacement toward the trimeric high-affinity CNTF receptor for LIF and CNTF. One study suggested that competition between the two factors is a result of three receptor components to establish a conformational site that is apparent for both LIF and CNTF.

多年来，研究表明 LIF 与包括睫状神经营养因子在内的各种其他因素相互作用。 两者通过它们的多聚体受体共享各种共同成分。 这两种细胞因子受体均含有 gp190/低亲和力 LIF 受体和 gp130/白细胞介素-60 受体传感器。 研究表明，LIF 和 CNTF 的三聚体高亲和力 CNTF 受体相互置换。 一项研究表明，这两个因素之间的竞争是三个受体成分建立一个对 LIF 和 CNTF 都很明显的构象位点的结果。

 

Mechanisms
When LIF binds to the LIF receptor also known as LIFR-a, a heterodimer is formed. This has a specific subunit and that is apparent for all members of this particularly receptor family. The formation of the heterodimer than leads to the activation of JAK/STAT as well as MAPK.
Typically, LIFe will be expressed in the trophectoderm of an embryo developing. The receptor, LIFR, is then expressed through the inner cell mass. Embryonic stem cells come from the inner cell mass during the blastocyst stage. As such, once they are removed, this also removes the LIF source.

当 LIF 与 LIF 受体（也称为 LIFR-a）结合时，会形成异二聚体。 这有一个特定的亚基，这对于这个特别受体家族的所有成员都是显而易见的。 异二聚体的形成导致 JAK/STAT 以及 MAPK 的激活。
通常，LIFe 将在胚胎发育的滋养外胚层中表达。 然后受体LIFR通过内细胞团表达。 胚胎干细胞来自囊胚阶段的内细胞团。 因此，一旦它们被删除，这也会删除 LIF 源。