29.6 Posterior development uses another localized regulator Order of posterior pathway mutants Loca lizatio n of p roduc tsin th e egg capuccino Comrmon pathway sprre Figure 29.8 The Staufen st妇fer p roteiry posterior pathway Oskar osk ar has two branches, mRNA responsible for Vasa protein abdominal vabis development and 业 dQ germ cell formation. Polar granu les? rk nown de termin ants A bdominal br anch Gem ce ll bra nch nanos nanos Pole ce lls mR NA fo rm pumifc nanos protein 清菜大当
Figure 29.8 The posterior pathway has two branches, responsible for abdominal development and germ cell formation. 29.6 Posterior development uses another localized regulator
Fertilized egg has two nuclei 29.6 Posterior development uses another localized Divisions 1-8(90 min) Nuclei divide in common cytoplasm (syncytium).Nuclei in polar plasm (pink) regulator become gem cell precursors. Figure 29.2 The early Syncvtial blastoderm (150 min) development of the Nuclei migrate to periphery and divide;4 further divisions occur(in close but not perfect synchrony). Drosophila egg occurs in a common cytoplasm until the stage of cellular blastoderm. ●e●●●●●eee●ee● Cellular blastoderm (195 min) Membranes surround nuclel to form monolayer of ~6000 somatic cells Qda色3 oopodo 情莘大学
Figure 29.2 The early development of the Drosophila egg occurs in a common cytoplasm until the stage of cellular blastoderm. 29.6 Posterior development uses another localized regulator
29.6 Posterior development uses another localized regulator Donor Wild-type embryo Figure 29.6 Mutant embryos that cannot develop can be rescued by injecting cytoplasm taken from a wild-type embryo.The donor can be tested for time of appearance and location of the rescuing Remove material from donor activity;the recipient can be and microinject into recipient tested for time at which it is susceptible to rescue and the effects of injecting material at Recipient different locations. Mutant embryo 清菜大兰
Figure 29.6 Mutant embryos that cannot develop can be rescued by injecting cytoplasm taken from a wild-type embryo. The donor can be tested for time of appearance and location of the rescuing activity; the recipient can be tested for time at which it is susceptible to rescue and the effects of injecting material at different locations. 29.6 Posterior development uses another localized regulator
29.6 Posterior nanos RNA is localized at the posterior end at the 3rd division development uses another localized regulator Figure 29.9 nanos products are localized at the posterior end of a Drosophila embryo.The upper photograph shows the tightly localized RNA inthe very early nanos protein spreads from the posterior end at the 8th division embryo (at the time of the 3rd nuclear division).The lower photograph shows the spreadingof nanos protein at the 8th nuclear division.Photographs kindly provided by Ruth Lehmann. 清菜大当
Figure 29.9 nanos products are localized at the posterior end of a Drosophila embryo. The upper photograph shows the tightly localized RNA inthe very early embryo (at the time of the 3rd nuclear division). The lower photograph shows the spreadingof nanos protein at the 8th nuclear division. Photographs kindly provided by Ruth Lehmann. 29.6 Posterior development uses another localized regulator
29.7 How are mRNAs and Nursecells Oocyte proteins transported and localized? RNA Figure 29.10 Some mRNAs are transported into the Drosophila egg as ribonucleoprotein particles.They move to their Ribonucleoprotein final sites of localization by association with tracks that may bicaid mRNA locaizes at anterior end; askar mRNA moves down tracks to postericr end be either either microtubules or actin filaments bicoid osKar mRNA R时A 清菜大当
Figure 29.10 Some mRNAs are transported into the Drosophila egg as ribonucleoprotein particles. They move to their final sites of localization by association with tracks that may be either either microtubules or actin filaments. 29.7 How are mRNAs and proteins transported and localized?