Parental expression and methylation of p57^Kip2 andLit1 during development. (A) Allelic expression and methylation of p57^Kip2 and Lit1 in F₁ mice. The mRNA and genomic DNA obtained from various tissues were used for RT-PCR and genomic PCR, respectively.HpaII and HhaI indicate restriction enzymes used for methylation-sensitive genomic PCR; +, digested; −, not digested. Tissues used for analyses were as follows: 7.5, 10.5, and 18.5 dpc embryos; NB, whole newborn; K, adult kidney; B, adult B6 kidney; P, adult PWK kidney. RT indicates reverse transcription; +, transcriptase added; −, no transcriptase. Primers are described in Methods. Two alleles were distinguished as described in Methods. F₁ hybrid mice were all BPF₁. (B) (Top) Schematic structure of p57^Kip2, Lit1, andKvlqt1. (Bottom) Schematic pattern of expression and methylation during development for p57^Kip2 andLit1, respectively. In expression, +, expressed; −, nonexpressed. In methylation, +, methylated; −, nonmethylated.