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A 30-kDa alternative translation product of the CCAAT/enhancer binding protein alpha message: transcriptional activator lacking antimitotic activity.

Publication ,  Journal Article
Lin, FT; MacDougald, OA; Diehl, AM; Lane, MD
Published in: Proc Natl Acad Sci U S A
October 15, 1993

Full-length (42 kDa) CCAAT/enhancer binding protein alpha (C/EBP alpha) (p42) has been implicated in the transcriptional activation of adipocyte genes including the 422(aP2) and C/EBP alpha genes during differentiation of 3T3-L1 preadipocytes. We have identified a 30-kDa isoform (p30) of C/EBP alpha that is expressed by 3T3-L1 adipocytes, mouse adipose tissue, and rat liver. In vitro translation of wild-type C/EBP alpha mRNA or transient transfection with a wild-type C/EBP alpha vector gave rise to similar levels of p42 and p30. Mutational analysis revealed that p30 is an alternative translation product initiated at the third in-frame methionine codon of the C/EBP alpha message. p30C/EBP alpha binds to the C/EBP sites within and activates reporter gene expression driven by the 422(aP2) and C/EBP alpha gene promoters. Although transfection of 3T3-L1 preadipocytes with a strong p30C/EBP alpha expression vector is insufficient to induce differentiation, this vector advances the differentiation program. Unlike p42C/EBP alpha, which inhibits cell proliferation, p30C/EBP alpha is not antimitotic. Thus, the N-terminal 12-kDa segment of full-length C/EBP alpha contains an amino acid sequence necessary for antimitotic activity. During differentiation of 3T3-L1 preadipocytes and during hepatocyte development, the cellular p42C/EBP alpha/p30C/EBP alpha ratio changes, raising the possibility of a regulatory role.

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Published In

Proc Natl Acad Sci U S A

DOI

ISSN

0027-8424

Publication Date

October 15, 1993

Volume

90

Issue

20

Start / End Page

9606 / 9610

Location

United States

Related Subject Headings

  • Transcriptional Activation
  • Transcription, Genetic
  • Transcription Factors
  • Regulatory Sequences, Nucleic Acid
  • Promoter Regions, Genetic
  • Nuclear Proteins
  • Molecular Weight
  • Mitosis
  • Mice
  • Liver
 

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Lin, F. T., MacDougald, O. A., Diehl, A. M., & Lane, M. D. (1993). A 30-kDa alternative translation product of the CCAAT/enhancer binding protein alpha message: transcriptional activator lacking antimitotic activity. Proc Natl Acad Sci U S A, 90(20), 9606–9610. https://doi.org/10.1073/pnas.90.20.9606
Lin, F. T., O. A. MacDougald, A. M. Diehl, and M. D. Lane. “A 30-kDa alternative translation product of the CCAAT/enhancer binding protein alpha message: transcriptional activator lacking antimitotic activity.Proc Natl Acad Sci U S A 90, no. 20 (October 15, 1993): 9606–10. https://doi.org/10.1073/pnas.90.20.9606.
Lin, F. T., et al. “A 30-kDa alternative translation product of the CCAAT/enhancer binding protein alpha message: transcriptional activator lacking antimitotic activity.Proc Natl Acad Sci U S A, vol. 90, no. 20, Oct. 1993, pp. 9606–10. Pubmed, doi:10.1073/pnas.90.20.9606.
Lin FT, MacDougald OA, Diehl AM, Lane MD. A 30-kDa alternative translation product of the CCAAT/enhancer binding protein alpha message: transcriptional activator lacking antimitotic activity. Proc Natl Acad Sci U S A. 1993 Oct 15;90(20):9606–9610.
Journal cover image

Published In

Proc Natl Acad Sci U S A

DOI

ISSN

0027-8424

Publication Date

October 15, 1993

Volume

90

Issue

20

Start / End Page

9606 / 9610

Location

United States

Related Subject Headings

  • Transcriptional Activation
  • Transcription, Genetic
  • Transcription Factors
  • Regulatory Sequences, Nucleic Acid
  • Promoter Regions, Genetic
  • Nuclear Proteins
  • Molecular Weight
  • Mitosis
  • Mice
  • Liver