Heterogeneity of smooth muscle myosin heavy chain expression at the
single cell level.
Meer, Daniel P., and Thomas J. Eddinger.
Department of Biology, Marquette University, Milwaukee, Wisconsin
53233
APStracts 2:0444C, 1995.
Expression of the smooth muscle myosin heavy chain (SM-MHC) isoforms
was examined in individual rabbit arterial smooth muscle cells using
reverse transcription-polymerase chain reaction (RT-PCR). The RT-PCR
amplification protocol used oligonucleotide primers complementary to
regions which flank the alternative exon which encodes the nine
unique amino acids found in the carboxyl terminal domain of SM2. RT
-PCR products of SM1 and SM2 mRNAs differ in length and
electrophoretic mobility. Partial DNA sequencing of the PCR products
confirmed SM1 and SM2 identity. Densitometric analyses of adjacent
samples extracted from the same tissues and processed for SM2:SM1
protein and PCR amplified SM2:SM1 RNA ratios exhibited a high
correlation (R=0.92). RT-PCR amplified SM2:SM1 mRNA ratios of
individual adult rabbit arterial cells ranged from 0.0-1.8 (n=59),
while multicellular vascular samples varied much less (0.4-0.6, n=5).
These results indicate that individual cells within a blood vessel
differ significantly in SM-MHC expression. This difference may be
important for the regulation of contraction in these vessels.
Received 6 October 1995; accepted in final form 5 December 1995.
APS Manuscript Number C608-5.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 December 95