Expression profile of Smtnl1 in various mouse and human tissues. In (A), an RT-PCR reaction (denoted 1; expected size, 440 bp) was performed on total RNA extracted from mouse skeletal muscle (SKM) and smooth muscle dissected from aorta (AO), ileum (ILM), colon (COL) and urinary bladder (BL). The RT-PCR was followed by nested PCR (denoted N; expected size, 313 bp) to increase the specificity and sensitivity of the detection. RT-PCR reactions of GAPDH (denoted G; expected size, 240 bp) was performed to control for the integrity of the extracted mRNA. Results are representative of replicate PCR reactions completed on cDNA synthesized from two separate mice. In (B), Northern blot analysis of Smtnl1 expression in human tissues was completed on a Clontech multi-tissue membrane with 1 μg polyA+ RNA loaded per lane. The membrane was hybridized overnight with a 32P-labeled Smtnl1 cDNA probe (1 - 1038 bp) and exposed to X-ray film. The major human Smtnl1 transcript of 2.1-kb is indicated by the arrowhead.