The CCAAT element in the CIWI promoter regulates transcriptional initiation in chicken primordial germ cells. Issue 9 (5th September 2014)

• Record Type: Journal Article
• Authors: Sohn, Yoon Ah; Lee, Sang In; Choi, Hee Jung; Kim, Hyun Jeong; Kim, Ki Hyun; Park, Tae Sub; Han, Jae Yong
• Is Part Of: Molecular reproduction and development. Volume 81:Issue 9(2014:Sep.)
• Page Start: 871
• Page End: 882
• Publication Date: 2014-09-05
• Subjects: Reproduction -- Periodicals; Molecular biology -- Periodicals; Molecular genetics -- Periodicals; Embryology -- Periodicals; 571.8
• DOI: 10.1002/mrd.22356
• Languages: English
• ISSNs: 1040-452X

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>SUMMARY</title> <sec id="mrd22356-sec-0001" sec-type="section"> <p>The P‐element‐induced wimpy testis (PIWI) protein, which associates with small non‐coding RNAs, is responsible for maintaining the integrity of germ cells and stem cells. Thus, transcriptional regulation of <italic>PIWI</italic> is critical for its effective functional modulation. In this study, we identified the promoter region of the <italic>PIWI</italic> homolog in chicken (<italic>CIWI</italic>), and investigated the transcriptional regulatory elements that control expression of <italic>CIWI</italic> in chicken primordial germ cells (PGCs). We constructed a vector that included the enhanced green fluorescent protein (<italic>eGFP</italic>) gene controlled by the 4‐kb <italic>CIWI</italic> promoter. The vector was expressed in chicken PGCs, but not in chicken embryonic fibroblasts. Based on promoter deletion and fragmentation assays, we found that a 252‐bp fragment of the <italic>CIWI</italic> promoter (−577 to −326 bp) was crucial for <italic>CIWI</italic> expression in PGCs. A CCAAT transcriptional regulatory element (−498 to −494 bp) was detected in the proximal region from the transcription initiation site of <italic>CIWI</italic>, and mutational analysis confirmed that this element regulates transcriptional initiation in chicken PGCs. Interestingly, the regions flanking the CCAAT element, which are positioned differently in <italic>HIWI</italic> (human), <italic>Miwi</italic> (mouse), and <italic>CIWI</italic> orthologs, were highly conserved. In addition, we predicted that specificity protein 1 (SP1) motifs modulate the transcriptional initiation of <italic>CIWI</italic> by binding to the 5'‐flanking regions of the CCAAT box. Overall, 252 bp of the <italic>CIWI</italic> promoter possessing the transcriptional regulatory element CCAAT is crucial for regulating <italic>CIWI</italic> gene expression in chicken PGCs. This promoter may be applicable for the regulation of <italic>CIWI</italic> expression during germ‐cell development. <italic>Mol. Reprod. Dev. 81: 871–882, 2014. © 2014 Wiley Periodicals, Inc</italic>.</p> </sec> </abstract>