A rapid and accurate test that distinguishes one allele from another was the focus of this investigation. To distinguish one allele from another, short oligonucleotide probes 12 bases in length attached to a glass slide were utilized (Table 2). Each probe represents a different low-resolution allele in the DQA1 region. Details of the application of these inkjet microfabricated arrays for HLA-DQA1 low-resolution typing of DNA samples from HLA class II reference panel (UCLA Tissue Typing Laboratory, CA) can be found in Haddock et al. HLA-
DQA1 microarrays were fabricated at the Houston Advanced Research Center, The Woodlands, Texas, using microspotting quill pins. Biotinylated polymerase chain reaction (PCR) products were allowed to hybridize to the prefabricated glass slides and hybridization signals detected using enzyme-labeled fluorescence (ELF) with the aid of a charged-couple device (CCD) camera.
Low-resolution alleles were successfully typed using a 189-base pair region of the HLA-DQA1 gene by observing easily recognizable positive hybridization patterns. In Fig. 2, detection of homozygous as well as heterozygous samples was accomplished by viewing probes fluorescing under UV light. All samples were obtained from UCLA's Standardized DNA Reference Panel for HLA class II. Each DNA sample was labeled with a letter or letters, which corresponded to the key provided in the Standard Reference Material. The results were compared to the key to verify that the HLA typing of the sample was the same. This type of array is important because it encompasses the use of short oligonucleotide probes that provide a high level of discrimination between alleles. Furthermore, this type of array serves as a model for typing other important gene regions in the HLA complex. It can also be used to generate arrays for the detection of single-base changes in other genes of interest. In order to test the above samples for HLA-DQA1 using microarray technology, a 4x5 DQA1 array was generated as illustrated in Fig. 3. DNA isolated from cervical cancer patients and normal controls were used for HLA DQA1 typing. The results indicated low-resolution typing of DQA1 of both homozygous and heterozygous individuals can be done using DNA microarray.
Was this article helpful?
The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.