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B. Ghosh, C. Charakova, E.N. Vithana, S.S. Bhattacharya; Identification of the Genetic Basis of Partial Penetrance Phenotype of RP11 Locus (PRPF31) on Chromosome 19q13.4 . Invest. Ophthalmol. Vis. Sci. 2005;46(13):3831.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: PRPF31 gene is one of the three pre–mRNA splicing factor genes involved in causing adRP. The unique feature of RP11 locus is the nonpenetrance symptoms and retinal changes in some obligate carriers of the disease allele. This clinical manifestation of RP could be due to a wild–type low expressing allele. In order to identify the novel sequence change in PRPF31 gene, responsible for the differential expression of PRPF31 alleles, the 6.2kb region, comprising the promoter, upstream of PRPF31 gene has been amplified and sequenced, where the genetic change might exist. Methods: The 6.2kb region upstream of PRPF31 gene was amplified by Expand Long Template PCR kit, from a heterozygote individual containing both the wild–type high and low expressing alleles. Using the amplified PCR product, smaller PCR fragments were obtained with internal primers. Sequence analysis was carried out on the small PCR fragments corresponding to the 6.2kb region with ABI 3100 automated sequencer. Results: PCR amplification and sequence analysis of the heterozygote individual revealed three novel changes in the 6.2kb region, which has not been reported in the ENSEMBL database. The first change was observed at –6.756kb, A→G (starting from the ORF of PRPF31 gene). The second change showed the absence of 1A at –6.018kb. The third change involved a deletion of 5 A’s upstream of –5.178kb. Work is in progression to locate other sequence changes in the remaining 5’ UTR and to confirm this segregation of identified changes in asymptomatic and symptomatic offsprings. Conclusions: The sequence variants observed in the heterozygote individual has not been reported in ENSEMBL. The functional consequences of these novel changes among the different wild–type alleles on the transcriptional activity shall be assessed by Luciferase Reporter Assay. In addition, other parts of the genomic region (other introns and 3’UTR) shall be screened to observe any other genetic changes that may influence transcription.
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