A novel maternally transcribed homeobox gene, Eso-1, is preferentially expressed in oocytes and regulated by cytoplasmic polyadenylation.
The homeobox gene families play important roles in the transcriptional regulation of gene expression prior to and during embryo development. To identify novel homeobox genes expressed in early embryonic development, we conducted a degenerated oligonucleotide polymerase chain reaction (PCR) to screen a mouse embryonic stem (ES) cell cDNA library. A novel homeobox-containing gene, Eso-1, which is preferentially expressed in ES cells and ovaries, was identified. The full-length Eso-1 cDNA was found to be 1,710 bp with a predicted homeodomain that has no significant homology to previously reported homeodomain proteins. Eso-1 was mapped to chromosome 14A3. Reverse transcription-polymerase chain reaction (RT-PCR) analyses showed that Eso-1 was expressed through oogenesis and continuing to be expressed through to the blastocyst stage. De novo expression of Eso-1 started at 13.5 days postcoitum in the ovaries, which coincides with the initiation of oogenesis. Northern blot analyses demonstrated that Eso-1 is preferentially expressed in both ovaries and ES cells as a 1.7-kb transcript. Results from whole mount in situ hybridization revealed that Eso-1 in oocytes showed increased expression from primordial to antral follicles. The 3'-untranslated region of Eso-1 transcripts contained cytoplasmic polyadenylation sequences while the length of poly (A) tails changed during oocyte maturation, indicating that Eso-1 expression is controlled by time-dependent translational activation. We suggest that the novel homeodomain protein, Eso-1, plays a role during oocyte maturation and early embryonic development.
Li
Hung
H
Institute of Molecular Biology, Academic Sinica, Taipei, Taiwan.
Tsai
Ming-Shiun
MS
Chen
Chun-Ying
CY
Lian
Wei-Cheng
WC
Chiu
Yung-Tsung
YT
Chen
Gin-Den
GD
Wang
Sue-Hong
SH
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003593:Cytoplasm / Q000378:metabolism*; D047108:Embryonic Development / Q000235:genetics*; D020224:Expressed Sequence Tags; D005260:Female; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox; D018398:Homeodomain Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D009865:Oocytes / Q000166:cytology / Q000378:metabolism*; D009866:Oogenesis / Q000235:genetics; D026723:Polyadenylation / Q000235:genetics; D016133:Polymerase Chain Reaction; D023121:RNA, Messenger, Stored / Q000235:genetics / Q000378:metabolism*; D013047:Specific Pathogen-Free Organisms; D013234:Stem Cells / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics; D014158:Transcription, Genetic; D039221:mRNA Cleavage and Polyadenylation Factors / Q000378:metabolism
C512201:Eso-1 protein, mouse; D018398:Homeodomain Proteins; D023121:RNA, Messenger, Stored; D014157:Transcription Factors; D039221:mRNA Cleavage and Polyadenylation Factors