摘要
Dear Editor, The PIWI proteins （originally P-element-induced wimpy testis in Drosophila） are predominantly present in the germ-line in diverse organisms and are involved in the processing of a class of small RNAs known as piRNAs （see Refs. for review）. The human PIWI protein family consists of four members： PIWIL1-4. Of these, PIWIL4 is known to have essential roles in the first phases ofspermatogenesis： its expression is restricted to gonocytes and it is required for transposon silencing. The lack of this gene in mice causes meiotic arrest in spermatogenesis.
Dear Editor, The PIWI proteins （originally P-element-induced wimpy testis in Drosophila） are predominantly present in the germ-line in diverse organisms and are involved in the processing of a class of small RNAs known as piRNAs （see Refs. for review）. The human PIWI protein family consists of four members： PIWIL1-4. Of these, PIWIL4 is known to have essential roles in the first phases ofspermatogenesis： its expression is restricted to gonocytes and it is required for transposon silencing. The lack of this gene in mice causes meiotic arrest in spermatogenesis.
