Human fibulin‐4: analysis of its biosynthetic processing and mRNA expression in normal and tumour tissues

FEBS Letters

Ryan, Michael P.⁴  Greene, Lisa M.⁴  Berger, Anne²  Sierra, Véronique³  Gallagher, William M.⁴  Conseiller, Emmanuel³  Laurent-Puig, Pierre¹ 

[1] Inserm U490, Laboratoire de Toxicologie Digestive, Faculté des Sts. Pères, 45 rue des Saints Pères, 75270 Paris Cedex 06, France;Service de Chirurugie Digestive, Hôpital Européen Georges Pompidou AP, Hôpitaux de Paris, 75015 Paris, France;Oncology Department, AVENTIS Pharma, 13 quai Jules Guesde, BP14, 94403 Vitry-sur-Seine Cedex, France;Conway Institute of Biomolecular and Biomedical Research, Department of Pharmacology, University College Dublin, Belfield, Dublin 4, Ireland

关键词: Fibulin;    Colon cancer;    Oncogene;    11q13;    Cell growth regulation;   

DOI  :  10.1016/S0014-5793(00)02389-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Here, we report the identification of a human orthologue of fibulin-4, along with analysis of its biosynthetic processing and mRNA expression levels in normal and tumour tissues. Comparative sequence analysis of fibulin-4 cDNAs revealed apparent polymorphisms in the signal sequence that could account for previously reported inefficient secretion in fibulin-4 transfectants. In vitro translation of fibulin-4 mRNA revealed the presence of full-length and truncated polypeptides, the latter apparently generated from an alternative translation initiation site. Since this polypeptide failed to incorporate into endoplasmic reticulum membrane preparations, it was concluded that it lacked a signal sequence and thus could represent an intracellular form of fibulin-4. Using fluorescence in situ hybridisation analysis, the human fibulin-4 gene was localised to chromosome 11q13, this region being syntenic to portions of mouse chromosomes 7 and 19. Considering the fact that translocations, amplifications and other rearrangements of the 11q13 region are associated with a variety of human cancers, the expression of human fibulin-4 was evaluated in a series of colon tumours. Reverse transcription-polymerase chain reaction analysis of RNA from paired human colon tumour and adjacent normal tissue biopsies showed that a significant proportion of tumours had ∼2–7-fold increases in the level of fibulin-4 mRNA expression. Taken together, results reported here suggest that an intracellular form of fibulin-4 protein may exist and that dysregulated expression of the fibulin-4 gene is associated with human colon tumourigenesis.

【 授权许可】

Unknown