SPEN-IN-1 (compound X1) is an inhibitor (blocker/antagonist) of protein factor SPEN with a Kd of 47 nM. SPEN-IN-1 is selective for RepA, a 431-nucleotide domain in Xist (the prototype non-coding RNA) consisting of 8.5 GC-rich motifs responsible for gene silencing.

Physicochemical Properties

Molecular Formula	C27H20N4O
Molecular Weight	416.47
Appearance	White to off-white solid powder
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: Please store this product in a sealed and protected environment (e.g. under nitrogen), avoid exposure to moisture and light.
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

ln Vitro	SPEN-IN-1 (0-100 μM) inhibits RepA-PRC2 and RepA-SPEN with IC50 values of 30 and 48 μM, respectively[1]. At Kd values of 400, 47, and 420 nM, respectively, SPEN-IN-1 inhibits RepA, PRC2, and SPEN[1]. In vitro and in cells, SPEN-IN-1 specifically ruins the connection between Xist and homologous proteins [1]. The accumulation of PRC2 and H3K27me3 is significantly inhibited by SPEN-IN-1 [1].
ln Vivo	In vivo, SPEN-IN-1 diminishes the RepA-SPEN interaction [1].
References	[1]. Targeting Xist with compounds that disrupt RNA structure and X inactivation. Nature. 2022 Apr;604(7904):160-166.

Solubility Data

Solubility (In Vitro)

DMSO :~66.67 mg/mL (~160.08 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (6.00 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 2.5 mg/mL (6.00 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	2.4011 mL	12.0057 mL	24.0113 mL
	5 mM	0.4802 mL	2.4011 mL	4.8023 mL
	10 mM	0.2401 mL	1.2006 mL	2.4011 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.