HIF-1 alpha Transcription Factor Assay Kit (Colorimetric)

• Reactivity: Hu
• Applications: Func, NULL
• Suitable Sample Type: Nuclear Extracts

HIF-1 alpha Transcription Factor Assay Kit (Colorimetric) Summary

• Description: HIF1A Transcription Factor Assay Kit is a colorimetric method for determining HIF-1-alpha DNA binding activity.
• Assay Type: Colorimetric
• Sample Volume: 10 uL/well. All samples should be assayed in duplicate at minimum.
• Kit Type: Transcription Factor Assay Kit (Colorimetric)
• Gene: HIF1A

Applications/Dilutions

• Dilutions:
  • Functional
  • Quantification

Packaging, Storage & Formulations

• Storage: Storage of components varies. See protocol for specific instructions.

Notes

This product is produced by and distributed for Abnova, a company based in Taiwan.

Alternate Names for HIF-1 alpha Transcription Factor Assay Kit (Colorimetric)

• AINT
• anti-HIF-1 alpha
• anti-HIF1A
• ARNT interacting protein
• ARNT-interacting protein
• Basic-helix-loop-helix-PAS protein MOP1
• BHLHE78
• Class E basic helix-loop-helix protein 78
• HIF 1A
• HIF1 alpha
• HIF-1 alpha
• HIF1
• HIF1A
• HIF-1a
• HIF-1alpha
• HIF-1-alpha
• HIF1-alpha
• hypoxia inducible factor 1 alpha subunit, hypoxia inducible factor 1 subunit alpha
• hypoxia inducible factor 1, alpha subunit (basic helix-loop-helix transcription factor)
• hypoxia-inducible factor 1-alpha
• Member of PAS protein 1
• member of PAS superfamily 1
• MOP1
• PAS domain-containing protein 8
• PASD8

Background

Hypoxia contributes to the pathophysiology of human disease, including myocardial and cerebral ischemia, cancer, pulmonary hypertension, congenital heart disease and chronic obstructive pulmonary disease (1). In cancer and particularly solid tumors, hypoxia plays a critical role in the regulation of genes involved in stem cell renewal, epithelial to mesenchymal transition (EMT), metastasis and angiogenesis. In the tumor microenvironment (TME), hypoxia influences the properties and function of stromal cells (e.g., fibroblasts, endothelial and immune cells) and is a strong determinant of tumor progression (2,3).

HIF-1 or hypoxia inducible factor 1 (predicted molecular weight 93kDa), is a transcription factor commonly referred to as a "master regulator of the hypoxic response" for its central role in the regulation of cellular adaptations to hypoxia. In its active form under hypoxic conditions, HIF-1 is stabilized by the formation of a heterodimer of HIF-1 alpha and ARNT/HIF-1 beta subunits. Nuclear HIF-1 engages p300/CBP for binding to hypoxic response elements (HREs). This process induces transcription and regulation of genes including EPO, VEGF, iNOS2, ANGPT1 and OCT4 (4,5).

Under normoxic conditions, the HIF-1 alpha subunit is rapidly targeted and degraded by the ubiquitin proteasome system. This process is mediated by prolyl hydroxylase domain enzymes (PHDs), which catalyze the hydroxylation of key proline residues (Pro-402 and Pro-564) within the oxygen-dependent degradation domain of HIF-1 alpha. Once hydroxylated, HIF-1 alpha binds the von Hippel-Lindau tumor suppressor protein (pVHL) for subsequent ubiquitination and proteasomal degradation (4). pVHL dependent regulation of HIF-1 alpha plays a role in normal physiology and disease states. Regulation of HIF-1 alpha by pVHL is critical for the suppressive function of FoxP3+ regulatory Tcells (6). Repression of pVHL expression in chronic lymphocytic leukemia (CLL) B cells leads to HIF-1 alpha stabilization and increased VEGF secretion (7).

References

1. Semenza, G. L., Agani, F., Feldser, D., Iyer, N., Kotch, L., Laughner, E., & Yu, A. (2000). Hypoxia, HIF-1, and the pathophysiology of common human diseases. Advances in Experimental Medicine and Biology.

2. Muz, B., de la Puente, P., Azab, F., & Azab, A. K. (2015). The role of hypoxia in cancer progression, angiogenesis, metastasis, and resistance to therapy. Hypoxia. https://doi.org/10.2147/hp.s93413

3. Huang, Y., Lin, D., & Taniguchi, C. M. (2017). Hypoxia inducible factor (HIF) in the tumor microenvironment: friend or foe? Science China Life Sciences. https://doi.org/10.1007/s11427-017-9178-y

4. Koyasu, S., Kobayashi, M., Goto, Y., Hiraoka, M., & Harada, H. (2018). Regulatory mechanisms of hypoxia-inducible factor 1 activity: Two decades of knowledge. Cancer Science. https://doi.org/10.1111/cas.13483

5. Dengler, V. L., Galbraith, M. D., & Espinosa, J. M. (2014). Transcriptional regulation by hypoxia inducible factors. Critical Reviews in Biochemistry and Molecular Biology. https://doi.org/10.3109/10409238.2013.838205

6. Lee, J. H., Elly, C., Park, Y., & Liu, Y. C. (2015). E3Ubiquitin Ligase VHL Regulates Hypoxia-Inducible Factor-1 alpha to Maintain Regulatory T Cell Stability and Suppressive Capacity. Immunity. https://doi.org/10.1016/j.immuni.2015.05.016

7. Ghosh, A. K., Shanafelt, T. D., Cimmino, A., Taccioli, C., Volinia, S., Liu, C. G., ... Kay, N. E. (2009). Aberrant regulation of pVHL levels by microRNA promotes the HIF/VEGF axis in CLL B cells. Blood. https://doi.org/10.1182/blood-2008-10-185686

Limitations

This product is for research use only and is not approved for use in humans or in clinical diagnosis. Kits are guaranteed for 6 months from date of receipt.

Publications for HIF-1 alpha Kit (KA1321)(3)

Publications using KA1321

• Tandrasasmita OM and Tjandrawinata RR. Upregulation of endogenous erythropoietin expression by DLBS6747, a bioactive fraction of Ipomoea batatas L. leaves, via increasing HIF1 alpha transcription factor in HEK293 kidney cells. J Ethnopharmacol. 2016-10-05 [PMID: 30685435]
• Heun Y, Pogoda K, Anton M et al. HIF-1a Dependent Wound Healing Angiogenesis In Vivo Can Be Controlled by Site-Specific Lentiviral Magnetic Targeting of SHP-2. Mol Ther 2017-04-20 [PMID: 28434868]
• Zhou Y, Li X, Zhang C et al. Hydrogen sulfide promotes angiogenesis by down-regulating miR-640 via the VEGFR2/mTOR pathway. Am J Physiol Cell Physiol 2015-11-25 [PMID: 26879375]

FAQs for HIF-1 alpha Kit (KA1321). (Showing 1 - 10 of 11 FAQs).

1. Why is there a difference between the theoretical MW for HIF1A and the observed MW for HIF-1 alpha?  ..show answer..
   • HIF1A, like many other proteins, has post-translational modifications. Depending on the size, amount and nature of the post-translational modifications, it can cause subtle to very large changes in molecular weight.
2. Which antibody(ies) do you recommend for the detection of HIF-1a by immunohistochemistry in the sections of paraffin-embedded mouse liver samples? I would appreciate if you can give me several choices and rank them in the order of performance. My goal is to distinguish HIF upregulation by prolyl hydroxylase inhibitor in different liver cells.  ..show answer..
   • All of our antibodies are of high quality and are well tested/validated in species/applications we list on the datasheet. However, we suggest the following four HIF-1 alpha antibodies based upon customer reviews, as well as the number of peer reviewed publications in which these products have been cited by researchers from reputed institutes. (1) HIF-1 alpha Antibody (H1alpha67) (cat# NB100-105) (cited in at least 218 peer reviewed publications) (2) HIF-1 alpha Antibody (cat# NB100-479) (cited in at least 51 peer reviewed publications) (3) HIF-1 alpha Antibody (H1alpha67) (cat# NB100-123 ) (cited in at least 38 peer reviewed publications) (4) HIF-1 alpha Antibody (cat# NB100-449) (cited in at least 31 peer reviewed publications).
3. I would like to know, does a path exist for detection of HIF 1 in venous blood before and after revascularization of the leg?   ..show answer..
   • We are not entirely sure if HIF-1 alpha will be present in the leg after revascularization. It may be present, but you may want to search the literature to see if this has been looked at before. If not, then this would certainly be an experiment worth doing.
4. What is the molecular weight (kDa) of protein HIF 1 alpha in western blot?  ..show answer..
   • The theoretical molecular weight of HIF 1-alpha is ~93kDa. However, you will likely see a band between 100-120kDa due to phosphorylation.
5. We got the Hif1a (NB100-105) antibody from you guys. I used the concentration that is mentioned on your website, but I am getting a band of a completely different size (~70kDa) and not the 120 kDa mentioned.  ..show answer..
   • HIF-1 alpha is a notoriously difficult protein to work with due to its rapid degradation. Therefore, the ~70kDa bands are most likely degradation products. It is very important to lyse the cells in hypoxic conditions. We strongly recommend lysing the cells directly into the Laemmli buffer and doing that quickly, so that the exposure to oxygen is minimized.Please go through our hypoxia related FAQs, you should find them very informative.Also, running a positive control may help confirm the band specificity in your samples. You may prepare them yourself or choose some from our catalog, for example: 1) HeLa Hypoxic / Normoxic Cell Lysate (NBP2-36452)2) HeLa Hypoxic (CoCl2) / Normoxic Cell Lysate (NBP2-36450)
6. I performed several Western Blots of HIF-1 alpha with different lysis buffers, whole lysates, and cytoplasm/nuclei extractions. I can’t seem to get a good western blot (poor signal, band much lower than expected, etc.). Can someone suggest some technical considerations/tricks I should consider using?  ..show answer..
   • A major issue that researchers working with HIF-1 alpha is degradation due to exposure to oxygen. In western blot, this results in a weaker band and/or the appearance of multiple low molecular weight bands (40-80 kDa). We recommend preparing the lysates after collection of cells/tissues as quickly as possible (on ice), preferably in a hypoxic chamber. We also recommend including a true hypoxia mimetic control (eg: cells treated with CoCl2, DMOG… etc.). The controls help distinguish your band of interest from potential degradation/dimer bands.For more troubleshooting tips and frequently asked questions regarding hypoxia/HIFs, you can refer to our hypoxia-related FAQs.
7. I am doing HIF1 westerns in HIF-overexpressing mouse liver and adipose tissue using Novus antirabbit HIF1a antibody with overnight incubation. I am getting strong bands around 90kDa. I am aware that HIF theoretical molecular weight is 93kDa, but in westerns, the HIF band is usually around 120kDa according to my internet research. Can someone let me know if I’m getting the right HIF band or just some non-specific bands? Thanks.  ..show answer..
   • (1)    HIF-1 alpha’s theoretical molecular weight is 93kDa. The post translationally modified/ubiquitinated form of HIF-1 alpha protein (fails to undergo proteasomal degradation) shows up as a band in the 110-130 kDa range on a Western blot.(2)    The dimeric protein may appear at a position above 200 kDa on non-reducing gels.(3)    Importantly, HIFs are among the most rapidly degradable proteins; therefore, sample preparation is highly important when analyzing HIF1 alpha or HIF2 alpha. When degraded, HIF-1 alpha may show up between 40-80 kDa position on Western blot. Degradation may be avoided by preparing the samples as soon as possible after collection of cells/tissues in hypoxic chamber. Notably, the tissues/cells should be kept on ice during lysate preparation and the lysates should be analyzed as soon as possible.(4)    For troubleshooting suggestions/feedback on more than 25 similar frequently asked questions, I would recommend visiting Novus page: FAQs - Hypoxia and HIFs (5)    Last but not the least, Novus technical support team may be contacted via email
8. I have Hif1a nuclear protein extract at -80C. I am wondering if anyone knows how long it would be good for at that temperature since HIf1a is known to be degraded easily.Thank you!  ..show answer..
   • You could try a few things to further inhibit the degradation.1) Use the protease inhibitors (if you are not already using them).2) Lyse cells into a buffer that contains SDS or LDS (eg: Laemmli's buffer), since SDS and LDS denature and inhibit proteases. Lysis may even be performed with reducing agents in the buffer (eg. DTT), but this will make your lysates unsuitable for BCA assay.3) Lysing samples rapidly ensures that the samples are instantly homogenized (it also shears DNA released by the SDS).5) Flash-freezing samples in liquid nitrogen rather than freezing at -80*C reduces the window of time for protease activity.6) Freeze samples in individual aliquots, instead of thawing the same vial multiple times.
9. I am curious to know the biochemical reactions of CoCl2 that mimic hypoxia. Is it that CoCl2 can bind any ubiquitin enzyme which regulates their degradation?  ..show answer..
   • CoCl2 inhibits PHD enzymes (the body’s “oxygen sensors”) by replacing the Fe ion with Co, preventing these enzymes from marking HIF-1 alpha for degradation. CoCl2-based hypoxia mimetic samples are often used as positive control in HIF analysis. For more troubleshooting tips and frequently asked questions regarding hypoxia/HIFs, you can refer to our hypoxia-related FAQs.
10. I am curious to know the biochemical reactions of CoCl2 that mimic hypoxia. Is it that CoCl2 can bind any ubiquitin enzyme which regulates their degradation?  ..show answer..
    • CoCl2 inhibits PHD enzymes (the body’s “oxygen sensors”) by replacing the Fe ion with Co, preventing these enzymes from marking HIF-1 alpha for degradation. CoCl2-based hypoxia mimetic samples are often used as positive control in HIF analysis. For more troubleshooting tips and frequently asked questions regarding hypoxia/HIFs, you can refer to our hypoxia-related FAQs.
11. Is cross-reactivity with HIF-2 alpha tested/predicted?  ..show answer..
    • Although we don’t have cross-reactivity data with regards to HIF-2 alpha, we predict minimal cross-reactivity based on low sequence similarity observed from BLAST analysis between HIF-1 alpha and HIF-2 alpha.
Show All 11 FAQs.

Bioinformatics

• Gene Symbol: HIF1A