LM/TK(LMTK-)

The LM/TK- (LMTK-) cell line is derived from murine fibroblasts and is characterized by the lack of thymidine kinase (TK) activity. This cell line is particularly useful in genetic and molecular biology research, where it serves as a model system for studying gene function, DNA replication, and recombination. The absence of TK in these cells allows for the selection of mutants or recombinant cells that have regained TK activity, making them valuable in studies involving TK-deficient mutants and for the selection of TK-positive clones following transfection with exogenous DNA. This cell line, derived from a sub-line of the L-M mouse fibroblast cell line which is resistant to BUdR, is potentially used for genetic and biochemical studies such as gene transfer and somatic cell hybridization. LM/TK- cells are commonly employed in research involving the herpes simplex virus (HSV) thymidine kinase gene, as they provide a crucial background for the selection of HSV-TK gene transformants. This has significant implications in gene therapy research, where HSV-TK is used in suicide gene therapy strategies to selectively kill cancer cells. Furthermore, these cells are utilized in the production of recombinant viruses and in the analysis of viral gene expression and replication. The LMTK- cell line thus plays a critical role in advancing our understanding of genetic manipulation and the development of therapeutic strategies.

37°C, 5% CO₂, humidified atmosphere.

1. Confirm that the vial remains deeply frozen upon delivery, as cells are shipped on dry ice to maintain optimal temperatures during transit.

2. Upon receipt, either store the cryovial immediately at temperatures below -150°C to ensure the preservation of cellular integrity, or proceed to step 3 if immediate culturing is required.

3. For immediate culturing, swiftly thaw the vial by immersing it in a 37°C water bath with clean water and an antimicrobial agent, agitating gently for 40-60 seconds until a small ice clump remains.

4. Perform all subsequent steps under sterile conditions in a flow hood, disinfecting the cryovial with 70% ethanol before opening.

5. Carefully open the disinfected vial and transfer the cell suspension into a 15 ml centrifuge tube containing 8 ml of room-temperature culture medium, mixing gently.

6. Centrifuge the mixture at 300 x g for 3 minutes to separate the cells and carefully discard the supernatant containing residual freezing medium.

7. Gently resuspend the cell pellet in 10 ml of fresh culture medium. For adherent cells, divide the suspension between two T25 culture flasks; for suspension cultures, transfer all the medium into one T25 flask to promote effective cell interaction and growth.

8. Adhere to established subculture protocols for continued growth and maintenance of the cell line, ensuring reliable experimental outcomes.

Mycoplasma contamination is excluded using both PCR-based assays and luminescence-based mycoplasma detection methods.

To ensure there is no bacterial, fungal, or yeast contamination, cell cultures are subjected to daily visual inspections.

For long-term preservation, place vials in vapor-phase liquid nitrogen at about −150 to −196 °C. Storage at −80 °C is acceptable only as a short interim step before transfer to liquid nitrogen.

Cryopreserved cell lines are shipped on dry ice in validated, insulated packaging with sufficient refrigerant to maintain approximately −78 °C throughout transit. On receipt, inspect the container immediately and transfer vials without delay to appropriate storage.

At Cytion, we stand behind the quality and viability of our products. We guarantee that our cells will be viable at the start of culture for 60 days after shipment from our facilities. We assure that all materials conform to the specifications described in the Certificate of Analysis and/or Product Sheet.

For full details, please refer to our Warranty Statement.