42S p48--the most abundant protein in previtellogenic Xenopus oocytes--resembles elongation factor 1 alpha structurally and functionally. |
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Authors: | I W Mattaj N J Coppard R S Brown B F Clark E M De Robertis |
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Affiliation: | Biozentrum, Basel University, Switzerland. |
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Abstract: | We have undertaken an immunological and biochemical analysis of the most abundant soluble protein of previtellogenic Xenopus oocytes, 42S p48. We show that this protein shares immunological cross-reactivity with elongation factor 1 alpha (EF-1 alpha). Direct assays of both 42S fractions and purified 42S p48 show that this cross-reactivity is of functional significance since 42S p48, like EF-1 alpha, can transfer charged amino acids to ribosomes. We further demonstrate that 42S p48 is degraded soon after the onset of vitellogenesis, while the EF-1 alpha concentration remains essentially unchanged during this transition. These properties of 42S p48 are discussed with regard to its role in oogenesis. |
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