Author/Editor		Smerdu, Vika
Title		Izražanje genskih prepisov za izooblike težkih verig miozina v različnih tipih mišičnih vlaken človeka
Translated title		Expression of myosin heavy chain transcripts within distinct types of human muscle fibres
Type		monografija
Place		Ljubljana
Publisher		Medicinska fakulteta
Publication year		2002
Volume		str. 66
Language		slo
Abstract		While four genes determine four major isoforms (I, IIA, IIX and IIB) of myosin heavy chains (MyHC) in adult rodent skeletal muscles, only three isoforms, MyHC-I, -IIA and -IIB, were found in mature human skeletal muscles. At the beginning of this study three human MyHC genes, coding for MyHC-I, embryonic and perinatal MyHC isoforms, had already been determined. It was known that two additional MyHC genes also exist, they were supposed to be expressed in type II fibres. Two clones from human MyHC cDNA library were found to be very similar to cDNA clones for MyHC-IIA and -IIX of rat. Thus it was presumed that they correspond to the two undefined genes on chromosome 17 and that they are expressed in type II fibres of adult human skeletal muscles. To verify this assumption, the expression of MyHC transcripts (mRNA), corresponding to the two clones and to the three known MyHC genes, were analysed for the first time in this study. The MyHC transcript expression was revealed by in situ hybridisation technique with specific radiolabelled RNA probes. Beside embryonic, perinatal and beta probe also two probes, corresponding to the two partly known cDNA clones, were synthesised by transcription in vitro technique. Considering high homology of the two cDNA clones with rat cDNA clones for MyHC-IIA and -IIX, the corresponding probes were designated as 2a and 2x probes. According to the pattern of MyHC transcript expression fibre groups were determined and correlated to histochemical phenotypes of fibres (type I, IIC, IIA, IIAB and IIB), demonstrated with histochemical reaction for myofibrillar adenosine triphosphatase (ATPase). To show MyHC isoform expression monoclonal antibodies specific for rat MyHC were used and metabolic profiles of fibres were determined according to the activity of oxidative enzyme nicotinamide adenine dinucleotide tetrazolium reductase (NADH-TR) and glycolytic enzyme a-glycerophosphate dehydrogenase (a-GPDH). (Abstract truncated at 2000 characters).
Descriptors		MYOSIN HEAVY CHAINS MUSCLE FIBERS, FAST-TWITCH MUSCLE FIBERS, SLOW-TWITCH TRANSCRIPTION, GENETIC MUSCLE, SKELETAL AGE FACTORS IN SITU HYBRIDIZATION HISTOCYTOCHEMISTRY ANTIBODIES, MONOCLONAL ADENOSINETRIPHOSPHATASE NADH TETRAZOLIUM REDUCTASE GLYCEROLPHOSPHATE DEHYDROGENASE RNA PROBES DNA, COMPLEMENTARY GENE EXPRESSION