EXPRESSION LEVEL OF RPS4 MESSENGER-RNA IN 39,X MICE AND 40,XX MICE

Contrary to the effects of X-chromosome monosomy in humans (Turner syn drome), XO mice are fertile and anatomically normal. The human RPS4X g ene encodes ribosomal protein S4 and escapes X-chromosome inactivation , and its haploinsufficiency has been suspected to contribute to Turne r syndrome. Therefore, we compared the expression level of mRNA of Rps 4 (the mouse homolog of RPS4X) between XX and XO mice using Northern b lot analysis. The XO/XX ratio of Rps4 mRNA obtained from Northern blot analysis was 0.9. There was no difference in the expression level of Rps4 mRNA between XX and XO mice. The difference in the RPS4/Rps4 tran scription pattern between humans and mice may contribute, at least in part, to the phenotypic difference in monosomy X between humans and mi ce.