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. 2008 Apr 1;22(7):908–917. doi: 10.1101/gad.1640708

Figure 1.

Figure 1.

Expression of the IAP and Line-1 retrotransposons and methylation of their regulatory regions in neonatal prepachytene testes. (A) Scheme for the development of mouse male germ cells. (Gonia) Spermatogonia; (Lep) leptotene; (Zy) zygotene; (Pachy) pachytene; (RSp) round spermatid; (Esp) elongated spermatid. (B) Schematic diagram of the Line-1 and IAP genes. The locations of the probes used for Northern blotting and bisulfite sequencing are indicated by filled and open boxes, respectively. The sequences of the 5′-noncoding regions of the Line-1 genes are different for type Gf and type A. The probe for the 3′-noncoding region of IAP recognizes the full-length and all deletion derivatives of IAP. (C,D) Northern blotting showing transcription of the Line-1 (C) and IAP (D) retrotransposon genes in testes from 2-wk-old MILI- and MIWI2-deficient mice. The 5′-noncoding regions of type Gf and type A Line-1 and the 3′-noncoding region of IAP were used as probes. (E,F) Bisulfite sequencing of Line-1 (E) and IAP (F) in MILI- and MIWI2-deficient germ cells. Spermatogonial cells from 6- to 12-d-old mice were purified from Oct4-EGFP transgenic mouse (Yoshimizu et al. 1999) testes. (E) The 5′-noncoding regions of type Gf and type A Line-1 (nucleotides 874–1156; GenBank accession no. D84391) and nucleotides 1251–1542 of M13002 were analyzed. (F) Two LTR regions from the 5.4-kb IΔ1-type IAP in chromosomes 3qD and 16qB2 were arbitrarily chosen for analysis. Filled and open circles represent methylated and unmethylated CpGs, respectively. The percentage of methylated CpGs is shown in parentheses.