Related Experiment Video

Updated: Aug 11, 2026

Formation of Covalent DNA Adducts by Enzymatically Activated Carcinogens and Drugs In Vitro and Their Determination by 32P-postlabeling
09:33

Formation of Covalent DNA Adducts by Enzymatically Activated Carcinogens and Drugs In Vitro and Their Determination by 32P-postlabeling

Published on: March 20, 2018

The biological interaction of cis- and trans-urocanic acid and DNA

D B Yarosh1, S D Gettings, L G Alas

  • 1Applied Genetics Inc., Freeport, New York 11520.

Photodermatology, Photoimmunology & Photomedicine
|June 11, 1992
PubMed

Insights

Neither cis nor trans urocanic acid isomers cause DNA damage or mutations, even with UV exposure. Studies using DNA binding, repair, and mutation assays found no evidence of urocanic acid

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Genotoxicology

Background:

  • Urocanic acid (UCA) is a product of histidine metabolism found in the skin.
  • Both cis and trans isomers of UCA exist, with potential implications for biological activity.
  • Concerns exist regarding the genotoxic potential of UCA, particularly under UV irradiation.

Purpose of the Study:

  • To investigate the potential of cis and trans urocanic acid isomers to induce DNA damage.
  • To assess the genotoxic effects of UCA isomers using a battery of in vitro assays.
  • To determine if UV irradiation of UCA isomers enhances DNA damage induction.

Main Methods:

  • DNA binding assessed using the 32P-postlabeling assay.
  • DNA repair induction measured by the unscheduled DNA synthesis (UDS) assay.
  • Mutagenicity evaluated with Salmonella typhimurium and Escherichia coli plate-incorporation assays.

Main Results:

  • No evidence of direct DNA binding by either UCA isomer was detected across a wide concentration range.
  • Neither isomer induced DNA repair (UDS) or mutations in bacterial assays.
  • UV irradiation of cis or trans UCA did not result in significant DNA damage under cell-surviving conditions.

Conclusions:

  • Under the tested conditions, neither cis nor trans urocanic acid isomers exhibit direct genotoxicity.
  • Urocanic acid does not appear to be a significant inducer of DNA damage or mutations, alone or when exposed to UV light.
  • These findings suggest a low risk of urocanic acid-induced genotoxicity in biological systems.

More Related Videos

Uracil-DNA Glycosylase Assay by Matrix-assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry Analysis12:19

Uracil-DNA Glycosylase Assay by Matrix-assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry Analysis

Published on: April 22, 2022

CD Spectroscopy to Study DNA-Protein Interactions06:48

CD Spectroscopy to Study DNA-Protein Interactions

Published on: February 10, 2022

Related Concept Videos

DNA Base Pairing02:27

DNA Base Pairing

Erwin Chargaff’s rules on DNA equivalence paved the way for the discovery of base pairing in DNA. Chargaff’s rules state that in a double-stranded DNA molecule,
Cis-regulatory Sequences02:02

Cis-regulatory Sequences

Cis-regulatory sequences are short fragments of non-coding DNA that are present on the same chromosomes as the genes that they regulate. These fragments serve as binding sites for transcriptional regulators, proteins that are responsible for controlling gene transcription and differential gene expression across cell types in eukaryotes. Cis-regulatory sequences can be close to the gene of interest or thousands of bases away in the DNA sequence; however, those sequences that are further away are...
Cooperative Binding of Transcription Regulators02:13

Cooperative Binding of Transcription Regulators

Transcriptional regulators bind to specific cis-regulatory sequences in the DNA to regulate gene transcription. These cis-regulatory sequences are very short, usually less than ten nucleotide pairs in length. The short length means that there is a high probability of the exact same sequence randomly occurring throughout the genome.  Since regulators can also bind to groups of similar sequences, this further increases the chances of random binding. Transcriptional regulators form dimers that...
Disubstituted Cyclohexanes: cis-trans Isomerism02:37

Disubstituted Cyclohexanes: cis-trans Isomerism

Depending upon the different spatial orientation of the substituents, the disubstituted cycloalkanes exhibit two types of stereoisomers. The cis isomers have the substituents on the same side of the ring, whereas the trans isomers have the substituents on the opposite sides. These stereoisomers exhibit different physical properties and cannot be interconverted without breaking the carbon-carbon bonds.
In cyclohexane, the substituents can occupy different positions generating distinct isomers.
Cis-regulatory Sequences02:02

Cis-regulatory Sequences

Cis-regulatory sequences are short fragments of non-coding DNA that are present on the same chromosomes as the genes that they regulate. These fragments serve as binding sites for transcriptional regulators, proteins that are responsible for controlling gene transcription and differential gene expression across cell types in eukaryotes. Cis-regulatory sequences can be close to the gene of interest or thousands of bases away in the DNA sequence; however, those sequences that are further away are...
Mutagenicity and Carcinogenicity01:25

Mutagenicity and Carcinogenicity

Mutagenicity and carcinogenicity refer to the ability of drugs to cause genetic defects and induce cancer, respectively. The International Agency for Research on Cancer (IARC) classifies agents into four groups based on their carcinogenic potential. Group 1 agents are known human carcinogens; group 2A agents are probably carcinogenic to humans; group 3 agents lack data to support their role in carcinogenesis; and group 4 includes agents for which data support that they are not likely to be...