Submission Number: LAU-4-328-150

Abstract Number: 3

THE ROLE OF LOCALIZED RNA IN CELL LINEAGE SPECIFICATION AND EMBRYONIC PATTERNING IN Xenopus laevis.

Malgorzata Kloc, Agnes Chan, Luetta Allen, Ruthie Zearfoss and Laurence Etkin

Univ. of Texas M.D. Anderson Cancer Center, Houston, TX ¹

Abstract:
Localization of RNAs is an important phenomenon that occurs in diverse organisms from yeast to man. The asymmetric distribution of RNAs during oogenesis in the frog, Xenopus laevis, is extremely important for cell lineage specification and proper patterning of the embryo. We have shown that there are several different pathways through which groups of RNAs localize to specific regions of the oocyte. One called the METRO or early pathway localizes RNAs to the vegetal cortex of oocytes during the very earliest stages of oogenesis. The other, called the late pathway, localizes a different group of RNAs during the mid to late stages. Each of these pathways utilizes different machinery and mechanisms for localization. We showed that the use of either pathway depends on the proper assembly of the appropriate localization machinery during specific stages of oogenesis. In addition, there may be cross talk between the two pathways such that the assembly of the late pathway may depend on the proper functioning of the early pathway. The decision of which pathway to use depends on the presence of specific "early" or "late" cis-acting elements in the 3UTRs of the RNAs. Also, we have discovered the presence of subelements within the 3UTRs of several of the early localizing RNAs that are critical for their association with specific structural components such as the germinal granules of the germ plasm. The function of several of the localized RNAs in germ cell function and embryonic patterning also will be discussed. .

Keywords: oogenesis, germ cell formation, embryonic patterning, rna localization

This abstract is being presented at: 11:30 AM in session:
Minisymposium XI: POLARITY OF THE EGG AND PREIMPLANTATION EMBRYO