The high-mobility group A
protein 1a (HMGA1a) is a well-documented
DNA-binding protein acting as an architectural transcription regulator. Recently,
HMGA1a protein has been identified as a
hypoxia-inducible
RNA-binding
trans-acting factor for aberrant splicing of
presenilin-2 (PS2)
pre-mRNA observed in the brains of sporadic
Alzheimer's disease. Interestingly, this aberrant splicing of PS2 was also observed in the brains of
bipolar disorder and
schizophrenia. Many downstream genes under the control of HMGA1a could be associated with
schizophrenia. On the other hand, many gene transcripts are aberrantly spliced in
schizophrenia. Therefore, we examined the expression at the
mRNA and
protein levels of this
DNA- and
RNA-binding factor HMGA1a in the lymphoblastoid cell lines obtained from 16
schizophrenia patients with age-matched controls. We observed markedly higher HMGA1a
mRNA and the increased
HMGA1a protein in the nuclear fractions of
schizophrenia patients. In contrast, there were no significant differences in the expression levels of HMGA1b, which is an alternatively spliced
isoform of HMGA1a. The present study is the first to report a significant upregulation of HMGA1a in
schizophrenia, suggesting its potential roles in both transcription and splicing of target genes linked with
schizophrenia.