Structure of the 5' region of the human hexokinase type I (HKI) gene and identification of an additional testis-specific HKI mRNA.
Biochim Biophys Acta
; 1493(1-2): 19-26, 2000 Sep 07.
Article
in En
| MEDLINE
| ID: mdl-10978502
ABSTRACT
We previously reported the structure of the human hexokinase type I (HKI) gene and provided direct evidence of an alternative red blood cell-specific exon 1 located in the 5' flanking region of the gene. Three unique HKI mRNA species have also been described in human spermatogenic cells. These mRNAs contain a testis-specific sequence not present in somatic cell HKI, but lack the sequence for the porin-binding domain necessary for HKI to bind to porin on the outer mitochondrial membrane. The present study reports a new mRNA isoform, hHKI-td, isolated from human sperm. hHKI-td mRNA contains both a testis-specific sequence at the 5' end common to the three other mRNA isoforms and an additional unique sequence. Screening of a cosmid library and analysis of the cosmids containing the HKI gene revealed that testis-specific sequences are encoded by six different exons. Five of these exons are located upstream from the somatic exon 1 (5.6-30 kb) and one within intron 1. This study shows that a single human HKI gene spanning at least 100 kb encodes multiple transcripts that are generated by alternative splicing of different 5' exons. Testis-specific transcripts are probably produced by a separate promoter that induces the expression of the HKI gene in spermatogenic cells.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Testis
/
RNA, Messenger
/
Hexokinase
Type of study:
Diagnostic_studies
Limits:
Humans
/
Male
Language:
En
Journal:
Biochim Biophys Acta
Year:
2000
Type:
Article
Affiliation country:
Italy