Question

5. (4) What will happen to dorsal/ventral patterning in Xenopus under the conditions listed below (a-h)? From the choices (1-3), select the single most plausible outcome for each experiment 1. No dorsal structures form. 2. Normal embryo development 3. Extra dorsal structures form a) Fertilization followed by a brief UV treatment and physical rotation of the embryo Fertilization followed by a brief UV treatment, then transplant of a ventral vegetal blastomere from a 32-celled embryo onto the dorsal vegetal side of a UV treated 32-celled embryo Transplant of a dorsal vegetal blastomere from a normal embryo to the ventral hemisphere of another normal embryo at an equivalent stage Fertilization followed by a brief UV treatment, then transplant of a dorsal vegetal blastomere from a 32-celled embryo onto the dorsal vegetal side of a UV treated 32-celled embryo b) c) d) e) GSK3 overexpression throughout a normal embryo. f) Inhibition of Dsh from being made in the oocyte using RNAi g) Vg1 expressed uniformly throughout the embryo h) Treatment with lithium immediately after fertilization. (Note: lithium has the ability to inhibit GSK-3)

Answer 1

A, 2, Normal embryo development

Once the fertilization followed after UV radiation with enough doses there will be temporary orientation of irradiated eggs 90degree natural vertical axis protect the eggs made into normal embryo development.

B, 3, extra dorsal structure form

The activation of dorsal - specific genes in the vegetal pole of ventralized forming activity 32- cell embryos after UV treatment maintain the same vegetal pole and posterior shift towards the dorsal side..

C, 1, no dorsal structure form

However twin formation of embryo cell different from cells of a recipient, it shows off- axis orientation..in twin formation and no effects on pattern formation..

D, 1, no dorsal structure form

The development outcome of dorsal after UV treatment embryo fail to develop dorsal axis structure..

E, 2, normal embryo development

GSk3 A/B Bovine embryo development and it's Activity during developmental stages make normal embryo development

F, 2, normal embryo development

RNAi is initiates long and double RNAs time processing activated oocytes to 33% made normal embryo development..

G, 3, extra dorsal structure form

VG1 expressed uniform embryo development through out the development..it showing Xnr1 stage embryo expression in endoderm..on the dorsal side of longer duration,it reach higher level than in central endoderm..