Joint action of two RNA degradation pathways controls the timing of maternal transcript elimination at the midblastula transition in Drosophila melanogaster.
Maternally synthesized RNAs program early embryonic development in many animals. These RNAs are degraded rapidly by the midblastula transition (MBT), allowing genetic control of development to pass to zygotically synthesized transcripts. Here we show that in the early embryo of Drosophila melanogaster, there are two independent RNA degradation pathways, either of which is sufficient for transcript elimination. However, only the concerted action of both pathways leads to elimination of transcripts with the correct timing, at the MBT. The first pathway is maternally encoded, is targeted to specific classes of mRNAs through cis-acting elements in the 3'-untranslated region and is conserved in Xenopus laevis. The second pathway is activated 2 h after fertilization and functions together with the maternal pathway to ensure that transcripts are degraded by the MBT.
Bashirullah
A
A
Program in Developmental Biology, Research Institute, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada.
Halsell
S R
SR
Cooperstock
R L
RL
Kloc
M
M
Karaiskakis
A
A
Fisher
W W
WW
Fu
W
W
Hamilton
J K
JK
Etkin
L D
LD
Lipshitz
H D
HD
D020413:3' Untranslated Regions; D000818:Animals; D001483:Base Sequence; D001755:Blastocyst / Q000378:metabolism*; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000196:embryology / Q000378:metabolism*; D019143:Evolution, Molecular; D005260:Female; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D010063:Ovum / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D012737:Sex Factors; D013997:Time Factors; D014981:Xenopus; D015053:Zygote / Q000378:metabolism
D020413:3' Untranslated Regions; D029721:Drosophila Proteins; D006360:Heat-Shock Proteins; C089272:Hsp83 protein, Drosophila; D012333:RNA, Messenger