title: Mature maternal mRNAs are longer than zygotic ones and have complex degradation kinetics in sea urchin.
abstract: Early in embryogenesis, maternally deposited transcripts are degraded and new zygotic transcripts are generated during the maternal to zygotic transition. Recent works have shown that early zygotic transcripts are short compared to maternal transcripts, in zebrafish and Drosophila species. The reduced zygotic transcript length was attributed to the short cell cycle in these organisms that prevents the transcription of long primary transcripts (intron delay). Here we study the length of maternal mRNAs and their degradation kinetics in two sea urchin species to further the understanding of maternal gene usage and processing. Early zygotic primary transcripts and mRNAs are shorter than maternal ones in the sea urchin, Strongylocentrotus purpuratus. Yet, while primary transcripts length increases when cell cycle lengthens, typical for intron delay, the relatively short length of zygotic mRNAs is consistent. The enhanced mRNA length is due to significantly longer maternal open reading frames and 3'UTRs compared to the zygotic lengths, a ratio that does not change with developmental time. This implies unique usage of both coding sequences and regulatory information in the maternal stage compared to the zygotic stages. We extracted the half-lifetimes due to maternal and zygotic degradation mechanisms from high-density time course of a set of maternal mRNAs in Paracentrotus lividus. The degradation rates due to maternal and zygotic degradation mechanisms are not correlated, indicating that these mechanisms are independent and relay on different regulatory information. Our studies illuminate specific structural and kinetic properties of sea urchin maternal mRNAs that might be broadly shared by other organisms.
authors.affiliation: Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa 31905, Israel.
authors.forename: Tsvia
authors.initials: T
authors.lastname: Gildor
authors.affiliation: Bioinformatics Core Unit, University of Haifa, Haifa 31905, Israel.
authors.forename: Assaf
authors.initials: A
authors.lastname: Malik
authors.affiliation: Bioinformatics Core Unit, University of Haifa, Haifa 31905, Israel.
authors.forename: Noa
authors.initials: N
authors.lastname: Sher
authors.affiliation: Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa 31905, Israel. Electronic address: sben-tab@univ.haifa.ac.il.
authors.forename: Smadar
authors.initials: S
authors.lastname: Ben-Tabou de-Leon
mesh_terms: D020413:3' Untranslated Regions; D000818:Animals; D002453:Cell Cycle; D004625:Embryo, Nonmammalian / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D006207:Half-Life; D007700:Kinetics; D000072741:Maternal Inheritance; D009865:Oocytes / Q000378:metabolism; D016366:Open Reading Frames; D009924:Organ Culture Techniques; D047328:Paracentrotus / Q000196:embryology / Q000235:genetics* / Q000378:metabolism; D020871:RNA Stability / Q000235:genetics; D012333:RNA, Messenger / Q000737:chemistry / Q000378:metabolism*; D023121:RNA, Messenger, Stored / Q000737:chemistry / Q000378:metabolism; D013045:Species Specificity; D047269:Strongylocentrotus / Q000196:embryology / Q000235:genetics* / Q000378:metabolism; D015053:Zygote / Q000378:metabolism
chemical_list: D020413:3' Untranslated Regions; D012333:RNA, Messenger; D023121:RNA, Messenger, Stored
keywords: Echinoderms; Embryonic development; Gene structure evolution; Intron delay; Maternal to zygotic transition; Transcript length; mRNA degradation