A transcription factor is usually scarce, nuclear, and part of a family that shares its DNA binding domain, which sets three requirements on every reagent in this class: a nuclear preparation with its own loading reference, cross reactivity data against the relatives expressed in the same tissue, and a readout that is location or target gene rather than abundance.
An srebf1 antibody and a factor cleaved to act
SREBF1 is held in the endoplasmic reticulum membrane and cleaved when sterols fall, so the active species is a smaller nuclear fragment and an srebf1 antibody has to state which form its epitope sees. Both bands belong in a figure claiming activation, and sterol depletion with a statin in lipid free medium is the control that produces the fragment.
A prdm16 antibody and a very large factor
PRDM16 is a large multidomain factor used as a beige and brown adipose marker, so a prdm16 antibody needs a low percentage gel and a long transfer, and a missing band is usually the transfer. Expression is restricted and cold inducible, which makes the housing temperature and the depot sampled part of the method rather than a detail.
A cux1 antibody and the isoforms proteolysis makes
CUX1 is processed into shorter isoforms with different DNA binding behaviour, so a cux1 antibody shows several bands and the epitope decides which are seen, which is why the expected masses belong in the method. It is also a tumour suppressor read for loss, so an internal positive population is what makes a negative interpretable.
An irf1 antibody and an interferon induced factor
IRF1 is induced rather than constitutive, so an irf1 antibody reports a condition and an unstimulated lane is what makes a positive meaningful. The family is large with shared domains, so specificity against the relatives matters, and nuclear translocation after stimulation is the readout that says the pathway ran rather than the protein exists.
A mafb antibody and a small leucine zipper factor
MAFB is a small basic leucine zipper factor that dimerises, so a mafb antibody reports the monomer on a reducing gel while the functional unit is a dimer whose partner decides the target genes. Expression marks particular myeloid and islet populations, so the cell type identified beside the stain is what carries the inference.
A bcl6 antibody and a lineage marker in pathology
BCL6 is scored as nuclear positivity in lymphoma classification, so a bcl6 antibody is used with a validated clone and a stated cutoff rather than as a free choice, and a germinal centre in the same section is the internal positive control. It is a repressor recruited into complexes, which is what an immunoprecipitation rather than a blot reports.
A tcf4 antibody and the name collision to avoid
TCF4 and TCF7L2 are different genes that have both been called TCF4 in the literature, so a tcf4 antibody has to be checked against the gene identifier rather than the name, and ordering the wrong one is a documented waste. One is a neurodevelopmental factor, the other a Wnt pathway partner, and no experiment wants both.
An n myc antibody and a factor with a short half life
N-MYC is degraded within minutes unless it is stabilised, so an n myc antibody often reports very little in an untreated cell and a proteasome inhibitor lane is what shows the reagent works. It is amplified in particular tumours, which is why a positive control line with known amplification is the comparison that makes an expression claim readable.
Questions people ask about foxo1 antibody
Why a nuclear extract?
These factors are scarce and nuclear. A whole cell lysate dilutes them below detection and carries no compartment information.
What controls a family cross reaction?
Cross reactivity data against the relatives expressed in that tissue, and ideally a knockout or knockdown lane.
Why is the name TCF4 a problem?
Two different genes have carried it. Order against the gene identifier, not the name.