The SALL4A protein, together with the TAT family of double oxygenase, regulates the oxidation process that enhances 5mC.

On November 10, molecular Cell published a research article online entitled Cooperative Action between SALL4A and TET Proteins in Stepwise Oxidation of 5-Methylcytosine, reporting on the oxidation process of 5-methyl cells (5mC) in mouse embryonic stem cells. the cytosine methylation modification of
mammalian DNA is considered to be the most stable metastasis, and under the role of maintenance DNA methyl transferase, DNA methylation information from the progenique cell genome is transmitted to the child cells in a semi-reserved replication manner through silk division.
Recent studies have found that TET family proteins can gradually oxidize 5mC into 5-hydroxymethyl cytosine (5hmC), 5-aldehyde-based cytosine (5fC) and 5-ethyl cytosine (5caC) and move towards eventual demethylation.
this dynamic change expands the plasticity of the prescicative genetic information carried by DNA methylation.
in the genome, the oxidation of 5mC is strictly controlled, and in some genomic regions 5hmC is stable, while in other genomic regions 5hmC is only an intermediate for further oxidation and methylation.
the molecular basis for this selective event is unclear.
the study, using a combination of affinity and purification of SILAC with protein quantitative mass spectrometry technology, found that the zinc finger domain protein SALLA4A tends to bind DNA containing 5hmC modification.
SALL4 is an important gene in early embryonic development, and its mutations can lead to Duane-radial ray syndrome, which is explicitly inherited from the normal chromosome.
embryos, which had been knocked out by the Sall4 gene, stopped developing during the bed and died quickly.
study found that in mouse embryonic stem cells, the SALL4A protein is primarily located in the enhancer, and its binding to chromatin is heavily dependent on the TAT1 protein.
further analysis of the cytosine modification status of THEL4A binding site on the genome found that the lack of stable 5hmC on these site points, but the rich product of further oxidation 5fC and 5caC, suggesting that SALL4A may promote further oxidation of 5hmC.
sure enough, knocking out Sall4 resulted in the accumulation of a higher level of 5hmC at the original SALL4A binding point, as knocking out Sall4 reduced the stable binding of TAT2 and was not conducive to further oxidation of 5hmC.
this work enriches the understanding of the DNA oxidation and dmethylation process regulated by TET family proteins, and puts forward the concept of 5mC collaborative step-by-step oxidation.
the understanding of the dynamics of DNA methylation and its role in embryonic stem cell function and reprogramming.
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