The use of restriction landmark genomic scanning to scan the mouse genome for endogenous loci with imprinted patterns of methylation.

Abstract

Restriction landmark genomic scanning (RLGS) has been used to screen endogenous loci for imprinted patterns of methylation. The screening method is based upon the identification of genetic variation in RLGS profiles between different strains and determining whether specific variant landmarks are transmitted equally to the progeny of reciprocal F1 matings. The RLGS profiles of C57BL/6 (B6) and DBA/2 (D2) and their reciprocal hybrids were produced with two enzyme combinations that used NotI as the landmark enzyme and two combinations that used BssHII. An estimated 13% of the spots are either B5- or D2-specific in these tests, giving a total of nearly 1000 variant loci that were examined for imprinted methylation. Three candidate loci for imprinted regulation were identified in these analyses. We also used crosses of more genetically diverse parents to increase the number of variant loci screened. Interspecific crosses of B6 with the M. musculus strain PWK and intrasubspecific crosses between B6 and the M. molossinus strain MSM expanded the levels of variation between the parental strains in the cross to an estimated 31% and 26%, respectively. The RLGS patterns for one NotI combination and one BssHII profile were examined for each of these crosses, giving approximately 2000 additional loci that were screened for imprinted patterns of methylation. Eight loci with imprinted patterns of transmission were observed out of 3040 loci tested. The chromosomal locations for the three B6 and D2 specific loci, Irlgs 1-3, were identified using BXD recombinant inbred strain analysis. Irlgs 1 and 3 are B6- and D2-specific loci that had the same strain distribution pattern which mapped to the central region of chromosome 9.(ABSTRACT TRUNCATED AT 250 WORDS)