Vertebrate Development Maternal to Zygotic Control (Advances in Experimental Medicine and Biology)

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Table 8.2

Germ line mRNAs in Xenopus

mRNA

Protein classification

Phenotype

Function

Reference

Dead-end (dndl)

RNA-binding (RRM)

Knockdown of dnd1

in oocyte interfered

with formation of vegetal cortical microtubule arrays. Mis-migration of PGCs in tailbud stages

Blocks miRNA repression in germ cells, PGC survival. Dnd1 anchors trim36 to vegetal cortex

Horvay et

al. (

2006

)

and Mei et

al. (

2013

)

Xdazl (dazl)

RNA-binding (RRM)

Knockdown of Xdazl inhibited migration from the ventral to the dorsal endoderm

Positive regulator of translation; promotes polyadenylation

Houston et

al. (

1998

)

and Houston and King (2000a

, b

)

XGrip (grip2)

Glutamate Receptor-

Interacting Protein

Knockdown and overexpression reduced average PGC number; PGCs mis-

localized

into anterior endoderm at tailbud stages. PGC migration to germinal ridges impaired

PGC development and migration

Tarbashevich et

al.

(^2007

), Claussen et

al.

(^2011

), and Kirilenko

et

al. (

2008

)

Sybu

Adapter protein binds KIF5b, syntaxin

Knockdown mRNA sybu caused loss of dorso-anterior axis formation in embryos

May play a role in protein that bridges microtubule motors and membrane vesicles, during dorsoventral axis formation in the vertebrates

Colozza and Robertis (^2014

)

Xpat (PGAT)

Unknown

Major constituent of germ plasm throughout oogenesis and early development. Also present in oocyte and embryo (i.e., nuclei)

May play a role in germ plasm formation, position and maintenance

Hudson and Woodland (^1998

) and Machado

et

al. (

2005

)

DeadSouth (ddx25)

DEAD box RNA helicase

Knockdown of DEADsouth inhibited migration of germ plasm from the cortex to perinuclear region and inhibited PGC division at stage 12. PGC number reduced after stage 20 when ddx25 overexpressed

ATP dependent RNA helicase

MacArthur et

al.

(^2000

) and Yamaguchi

et

al. (

2013

)

Germes

Unknown; associates with dynein light chains

Overexpression of germes resulted in number of primordial germ cells and abnormalities in germ plasm distribution

Translocation of germ plasm from cortex to perinuclear region during gastrulation; germ plasm organization

Berekelya et

al. (

2003

,

2007

) and Yamaguchi

et

al. (

2013

)

Trim36

E3 Ubiquitin-Protein Ligase

Trim36 mRNA found in mitochondrial cloud of stage I oocytes. Vegetal microtubule polymerization and cortical rotation were disrupted in trim36-depleted embryos

Regulates microtubule array formation during cortical rotation involved in dorsal axis formation

Cuykendall and Houston (

2009

),

Yoshigai et

al. (

2009

),

and Mei et

al. (

2013

)

T. Aguero et al.