Identification of Genes required for

Cytoplasmic Localizationin

Early C. elegans Embryos

Background

Development of C.elegans

Development• After fertilization, the two pronucleis join together.

http://www.mbg.cornell.edu/cals/mbg/research/kemphues-lab/movies.cfm/kjk1_wt

Development• Then the mitotic spindle forms, and it migrates posteriorly.

http://www.mbg.cornell.edu/cals/mbg/research/kemphues-lab/movies.cfm/kjk1_wt

Development• Owing to the migration, the two daughter blastomeres are produced in diff

erent sizes after the first cleavage.

http://www.mbg.cornell.edu/cals/mbg/research/kemphues-lab/movies.cfm/kjk1_wt

Development• At the second cleavage, AB divides transversely and P1 divides

longitudinally. AB always divides before P1.

http://www.mbg.cornell.edu/cals/mbg/research/kemphues-lab/movies.cfm/kjk1_wt

Principles of Development (Lewis Wholper) Chapter 5

• After fertilization, the two pronucleis join together.

• Mitotic spindle forms, and it migrates posteriorly. • Daughter blastomeres are produced in different

sizes after the first cleavage.• AB＞ P1• P granules are localized to P1• At the second cleavage, AB divides transversely

and P1 divides longitudinally. • AB always divides before P1• P granules are localized to P2

• After fertilization, the two pronucleis join together.

• Mitotic spindle forms, and it migrates posteriorly. • Daughter blastomeres are produced in different

sizes after the first cleavage.• AB＞ P1• P granules are localized to P1• At the second cleavage, AB divides transversely

and P1 divides longitudinally. • AB always divides before P1• P granules are localized to P2

The Result

Genes

Defects

• Equal First Cleavage

• Altered Orientation of Second Cleavages

• Synchronous Cleavages

• Abnormal Localization of P Granule

Aim

To identify the genes required for cytoplasmic localization

in early C. elegans embryos

Sub-Questions

http://www.mbg.cornell.edu/cals/mbg/research/kemphues-lab/research-details.cfm

Identify The Genes

Screening There are four categories of mutation, but three of them

are hard to observe.

So they chose the forth.

Linkage Mapping Linkage Analysis

Meiotic Recombination

Complementation

Identify The Defects

• Equal First Cleavage

• Altered Orientation of Second Cleavages

• Synchronous Cleavages

• Abnormal Localization of P Granule

Equal First Cleavage

Equal First Cleavage

• Blastomere Size Measurement

• Spindle Movement Measurement

Equal First Cleavage

Equal First Cleavage

Altered Second Cleavages

Altered Second Cleavages

Altered Second Cleavages

Synchronous Cleavages

Synchronous Cleavages

• par-1 and par-4 cleave synchronously up until fourth or fifth cleavage

• par-2 and par-3 are rather earlier

Abnormal Localization of P Granule

Abnormal Localization of P Granule

Abnormal Localization of P Granule

Identify The Phenotype

• Differentiated Cell Types

• Grandchildless

The Result

Summary