Changes in gene expression at the precursor --> stem cell transition in leech.
The glossiphoniid leech, Theromyzon trizonare, displays particularly large and accessible embryonic precursor/stem cells during its early embryonic cleavages. We dissected populations of both cell types from staged embryos and examined gene expression profiles by differential display polymerase chain reaction methodology. Among the approximately 10,000 displayed cDNA fragments, 56 (approximately 0.5%) were differentially expressed at the precursor --> stem cell transition; 29 were turned off (degraded, precursor-specific); and 27 were turned on (transcribed, stem cell-specific). Several putative differentially expressed cDNAs from each category were confirmed by Northern blot analysis on staged embryos. DNA sequencing revealed that 19 of the cDNAs were related to a spectrum of genes including the CCR4 antiproliferation gene, Rad family members, and several transcriptional regulators, while the remainder encoded hypothetical (10) or novel (27) sequences. Collectively, these results identify dynamic changes in gene expression during stem cell formation in leech and provide a platform for examining the molecular aspects of stem cell genesis in a simple invertebrate organism.
Hohenstein
Kristi A
KA
Biology Department, Rutgers, The State University of New Jersey, 315 Penn Street, Camden 08102, USA.
Shain
Daniel H
DH
D000818:Animals; D015152:Blotting, Northern; D018076:DNA, Complementary / Q000235:genetics; D005786:Gene Expression Regulation / Q000502:physiology; D007865:Leeches / Q000235:genetics / Q000502:physiology*; D016133:Polymerase Chain Reaction; D011506:Proteins / Q000235:genetics; D013234:Stem Cells / Q000166:cytology* / Q000502:physiology*; D014158:Transcription, Genetic
D018076:DNA, Complementary; D011506:Proteins