cDNA cloning and mRNA expression of cat and dog Cdkal1

Abstract

The cyclin-dependent kinase 5 regulatory subunit-associated protein 1-like 1 (CDKAL1) gene encodes methylthiotransferase, and the gene contains risk variants for type 2 diabetes in humans. In this study, we performed complementary DNA cloning for Cdkal1 in the cat and dog and characterized the tissue expression profiles of its messenger RNA. Cat and dog Cdkal1 complementary DNA encoded 576 and 578 amino acids, showing very high sequence homology to mammalian CDKAL1 (>88.4%). Real-time polymerase chain reaction analyses revealed that Cdkal1 messenger RNA is highly expressed in smooth muscle and that tissue distribution of Cdkal1 is similar in cats and dogs. Genotyping analysis of single-nucleotide polymorphism for cat Cdkal1 revealed that obese cats had different tendencies from normal cats. These findings suggest that the cat and dog Cdkal1 gene is highly conserved among mammals and that cat Cdkal1 may be a candidate marker for genetic diagnosis of obesity.

Keywords: Cdkal1; Q-PCR; cDNA cloning; cat; dog; obese.

Figure 1

Comparison of the cyclin-dependent kinase 5 regulatory subunit–associated protein 1–like 1 (Cdkal1) amino acid sequence of cats with those of other animals. Notes: The amino acid sequence of cat Cdkal1 (AB720722) was aligned with those of dog Cdkal1 (AB720723), human CDKAL1 (NP_060244), cow Cdkal1 (NP_001179620), mouse Cdkal1 (NP_653119), frog Cdkal1 (NP_989194), chicken Cdkal1 (XP_418914), and salmon Cdkal1 (NP_001167148). Dots matched to cat Cdkal1. Single underline indicates UPF0004 domain, double underline indicates radical S-adenosylmethionine domain, and broken underline indicates tRNA-binding domain.

Figure 2

Tissue distribution profile of cyclin-dependent kinase 5 regulatory subunit–associated protein 1–like 1 (Cdkal1) mRNA in the dog (left; open box bars) and cat (right; closed box bars). Notes: The expression levels of Cdkal1 mRNA in tissues of a 2-year-old male dog and a 3-year-old male cat were determined by real-time polymerase chain reaction. Each value of Cdkal1 mRNA was normalized to that of beta-actin mRNA and is the mean ± standard error of mean (n = 3) of triplicate experiments for an individual RNA sample. The statistical analysis was performed using Tukey’s test following analysis of variance. Values with different letters are significantly different (P < 0.05) in each dog and cat.