Intron-less processed Pcdhalpha genes in the central nervous system.

The genomic organization of the Pcdhalpha is remarkably similar to those of T-cell receptor and immunoglobulin genes. To elucidate the somatic rearrangements of the genomic DNAs of Pcdhalphas in the central nervous system, we screened a genomic brain library of the C57BL/6 mouse strain. From this screening we isolated an unusual, rearranged genomic Pcdhalpha DNA. This clone contained an intron-less Pcdhalpha v6 gene resembling the cDNA generated from its mRNA, inserted into the 28S rDNA gene locus. The intron-less Pcdhalpha v6 gene possessed a putative promoter region and 10 nucleotide substitutions but no poly(A) signal. Both edges of the integration site had additional 5-bp duplicated sequences. PCRs that were performed using primers for intron-less Pcdhalphas amplified products from genomic DNAs only in the brain; moreover, using the size-fractionated genomic DNA by sucrose density gradient centrifugation, intron-less Pcdhalpha is mainly amplified in the small size fraction of the genomic DNA. Inverted PCR for this small size fraction also amplifies the Pcdhalphas connecting the both ends with repeat sequences. These features suggest the somatic reverse-transcription, circularization, and rare occasion of integration into the genome of Pcdhalpha in the brain.

KEYWORDS: {{ getKeywords(articleDetailText.words) }}