Anti-METTL23 Polyclonal Antibody Contributes to Studies of Intellectual
Disabilities in Children

A team of Austrian and Canadian researchers led by Dr. Windpassinger characterized a new gene for autosomal recessive intellectual disability. It has been known that mutations cause pontocerebellar hypoplasia type 2A (OMIM:277470) and type 4 (OMIM:225753) - neurodegenerative disorders with chorea, dystonia or spasticity. Despite previous genetic studies, however, the mutated genes and their physiological role in the central nervous system have been elusive. A genome-wide sequencing and microarray analysis enabled Windpassinger's team to identify deletions and nonsense mutations in a new gene: METTL23 gene (Methyltransferase-like protein 23, C17orf95, Q86XA0 (MET23_HUMAN), NM_001206983.1 (isoform 1) and NM_001206986.1 (isoform 2)).

"Abcepta's custom projects have been cited in thousands of peer review publications, said Dr. John Mountzouris, Abcepta Site Leader. These antibodies and synthetic peptides have been instrumental in discoveries of new gene-functions or in determining immunohistochemical signatures with high prognostic value. For example, Abcepta anti-SHP2 antibody (AP8471e) has been used for the study of stage I-III colorectal carcinoma – the third most commonly diagnosed cancer in men and second in women worldwide. With the Windpassenger results published in Human Molecular Genetics, Abcepta is gratified to contribute to the development of an anti-METTL23 antibody used for research and discovery into the neuropsychiatric pathology associated with dysfunction of a gene essential to human cognition."

Bernkopf et al. described a polyclonal antiserum recognizing full-length METTL23 protein expressed in Escherichia coli. This polyclonal antiserum was used to confirm that the nonsense mutation in METTL23 found in two affected girls (PK31) results in a truncated METTL23 protein. Bernkopf et al. performed a test by immunoprecipitation of METTL23 from lymphoblastoid cells and subsequent detection with a sequence-specific antibody reacting with intact METTL23. The test revealed a strong signal of 21.5 kDa in controls but not in the patient. This observation has confirmed that the PK31-nonsense mutation does result in the loss of C-terminal METTL23 protein sequence.

The sequence-specific anti-METTL23 antibody (PAb) was raised by immunization with a synthetic peptide (located at the C-terminal 137-166 amino acid), manufactured by Abcepta. Using this PAb the authors proved the identity of the recombinant METTL23 by Western Blot. The dilution of the anti-METTL23 PAb was 1:300. Visualization was done by CleanBlot HRP Kit (goat IgG 1:100 000) purchased from Thermo. The PAb sensitivity was as low as 50 ng of the control METTL23. The METTL23-band detected by Western Blot was not detected in the patients.

The successful generation of an anti-METTL23 PAb testifies that Abcepta's synthetic peptides possess both the purity and quality necessary to generate a strong and specific antibody!

The full report by Bernkopf et al 2014 is available for download from PubMed (http://www.ncbi.nlm.nih.gov/pubmed/24626631) or from Human Molecular Genetics (http://hmg.oxfordjournals.org/content/early/2014/03/12/hmg.ddu115).

By John Mountzourts, Ph.D.