Cloning and characterization of a novel isoform of iodotyrosine dehalogenase 1 (DEHAL1) DEHAL1C from human thyroid: comparisons with DEHAL1 and DEHAL1B.
The human iodotyrosine dehalogenase 1 (DEHAL1) gene is composed of six exons. Two isoforms (DEHAL1 and DEHAL1B) have been published in GenBank, both of which have a nitroreductase domain and arise from differential splicing in exon 5. We recently showed that the DEHAL1 isoform is a transmembrane protein that efficiently catalyzes the NADPH-dependent deiodination of mono (L-MIT) and diiodotyrosine (L-DIT) in human embryonic kidney-293 (HEK293) cells. In the present study, we establish the existence of a new transcript, DEHAL1C, in the human thyroid with a terminal exon that lacks in the DEHAL1 transcript. This exon is the complete exon 5, which is spliced in the DEHAL1B mRNA variant. These two variants encode proteins with differing C-terminal domains. Using quantitative reverse transcription polymerase chain reaction, we found that the expression of the mRNA of DEHAL1C and DEHAL1B was lower than that of DEHAL1 mRNA in the thyroid. We also observed that human DEHAL1B and DEHAL1C proteins are rapidly degraded in stably transfected HEK293 cells, unlike the DEHAL1 protein, and that exposure to the proteasome inhibitor MG132 resulted in accumulation of these proteins that was markedly time- and concentration-dependent. These findings show that the cytoplasmic tail could play a role in the stability of the protein.
Gnidehou
Sédami
S
FRE 2939 CNRS, Institut Gustave Roussy, Villejuif, France., Laboratoire de Pharmacologie et d'Hormonologie, ISBA, Cotonou, Benin, France.
Lacroix
Ludovic
L
Sezan
Alphonse
A
Ohayon
Renée
R
Noël-Hudson
Marie-Sophie
MS
Morand
Stanislas
S
Francon
Jacques
J
Courtin
Françoise
F
Virion
Alain
A
Dupuy
Corinne
C
D017398:Alternative Splicing; D002460:Cell Line; D003001:Cloning, Molecular; D004305:Dose-Response Relationship, Drug; D005091:Exons; D006801:Humans; D006867:Hydrolases / Q000737:chemistry* / Q000235:genetics*; D007976:Leupeptins / Q000494:pharmacology; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics*; D008954:Models, Biological; D008957:Models, Genetic; D020033:Protein Isoforms; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013961:Thyroid Gland / Q000378:metabolism*; D013997:Time Factors
D007976:Leupeptins; D008565:Membrane Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D006867:Hydrolases; C497447:IYD protein, human; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde